GIFT  OF 

LFWARY 


, 


PR  A  C  TIC  A  L  INS  TR  UC  TION  FOR    YO  UNG 

ENGINEERS  AND   STEAM 

USERS. 


BY 


Egbert  Pomeroy  Watson, 

Editor  and  Proprietor  of  THE  ENGINEER. 


AUTHOR   OF 

Modern  Practice  of  American  Machinists    and  Engineers 

-Manual  of  the  Hand  Lathe— The  Professor 

in  the  Machine  Shop.  Etc.,  etc. 


Copyright,  March,  1892. 

150  NASSAU  STREET, 

NEW  YORK. 

1892: 


Prefaces  have  gone  out  of  fashion.     They  are  usually 
excuses,   or  explanations,   or  apologies,  or  something 
akin,  for  having  written  what  follows  them.     This  little 
book  needs  no  preface,  but  here  is  one  and  a  dedication 
as  well,  for  in  this  work  I  have  endeavored  to  serve 
young  American  Engineers  who  have  taken  to  the  busi- 
ness seriously  by  mentioning  a  few  troubles  they  are 
likely  to  encounter,  but  it  is  only  mention,  for  the  one 
thing  which  can  not  be  imparted  is  experience.     Time, 
study,  and  practice  alone  can  give  it.    No  man  was  ever 
,  made  an  en^ipecr  |>y  a  book  or  by  rules,  but  every  en- 
,ginee,r 'jAult&rxDvr^he  first  principles  and  traditions  of 
.ty»  Jxiaiwefs.  I  Tbe   inexperienced  will   find  a  few  of 
:thecrttferein.":*  * 

This  little  book  is  dedicated  to  American  Engineers, 
the  men  who  have  always  helped  me  on  my  way  and 
who  have  always  kept  faith  with  me;  who  have  always 
held  out  the  right  hand  of  fellowship  to  me  as  man  and 
boy,  by  their  sincere  friend  and  well  wisher. 

EGBERT  POMEROY  WATSON, 
February  i,  1892.  150  NASSAU  STREET,  N.  Y. 


GIFT  OF 
ENGINEERING  LFBRAIIT 


IKDRX. 


CHAPTER  I. 

Cleaning  the  Boiler PAGE  l 

Removing  Scale- 5 

CHAPTER  II. 

Using  Scale  Preventers 7 

Oil  in  Boilers --- 9 

Braces  and  Stays -- 9 

CHAPTER  III. 

Mud  Drums  and  Feed  Pipe  ---                                    11 

Boiler  Fittings ----  13 

CHAPTER  IV. 

Grate  Bars  and  Tubes - 15 

Bridge  Walls---- -  17 

The  Slide  Valve  Throttling  Engine -  18 

CHAPTER  V. 

The  Piston --- 22 

The  Slide  Valve---- -                       24 

CHAPTER  VI. 

Testing  the  Valve  with  Relation  to  the  Ports 27 

Defects  of  the  Slide  Valve -  30 

CHAPTER  VII. 

Lap  and  Lead •  --• 33 

The  Pressure  on  a  Slide  Valve  34 

Stem  Connections  to  the  Valve 36 

CHAPTER  VIII. 

Valves  off  their  Seats 40 

Valve  Stem  Guides -  41 

Governors 42 

Running  with  the  Sun    --  -- 44 


865694 


CHAPTER  IX. 

Eccentrics  and  Connections 46 

The  Crank  Pin --                    ---  48 

Brass  Boxes V 51 

Bearing  on  Pins  —  53 

Fitting  Brasses  to  Bearings 55 

CHAPTER  X. 

Adjustment  of  Bearings  --  57 

The  Valve  and  Gearing --      59 

CHAPTER  XI. 

Setting  Eccentrics 65 

The  Actual  Operation --  67 

CHAPTER  XII. 

Return  Crank  Motion - 74 

Pounding        75 

The  Connections : - 77 

Lining  Up  Engines 82 

CHAPTER  XIII. 
MakingJoints 88 

CHAPTER  XIV. 
Condensing  Engines 93 

CHAPTER  XV. 

Torricelli's  Vacuum loo 

Proof  of  Atmospheric  Pressure  -  -  101 

No  Power  in  a  Vacuum ---  101 

Pumps -  105 

CHAPTER  XVI. 
Supporting  a  Water  Column  by  the  Atmosphere 107 

CHAPTER  XVII. 
Starting  a  New  Plant 114 

CHAPTER  XVIII. 

The  Highest  Qualities  Demanded -  -  122 

The  Man  Himself  the  Factor - -  123 

Lastly - 124 


HOW  TO  RUN  ENGINES  .MTBMS,    >, 


CHAPTER    I. 

The  first  thing  to  be  done  upon  taking 
charge  of  an  engine  and  boiler,  new  or  old, 
is  to  examine  the  boiler  thoroughly.  No 
matter  whether  it  has  just  come  from  the 
shop,  or  has  been  run  for  years,  take  off  the 
man-hole  plate  and  go  inside  yourself  with 
a  hand-lamp  ;  after  you  are  in  look  at  all  the 
water  spaces,  and  see  if  they  are  clean,  that 
is,  without  rubbish  or  dirt  of  any  kind.  Even 
new  boilers  are  not  free  from  this.  There 
are  various  irresponsible  persons  about 
boiler  shops  who  are  not  as  careful  as  they 
should  be,  and  it  will  be  the  exception  rather 
than  otherwise  if  you  do  not  find  a  lot  ot 
things  which  are  better  out  of  the  boiler  than 
in  it.  In  large  boilers  rivet  kegs  are  often 
taken  in  to  sit  upon,  and  are  not  always  taken 
out  again  ;  the  staves  are  thrown  down  in  the 
water  space,  from  whence  they  will  float  out 
and  get  in  the  steam  pipes  by  some  mysterious 
happening.  The  water  line  is  not  so  high  as 
the  steam  pipe,  by  any  means,  but  the  staves 
get  there  somehow  ;  so  do  bunches  of  waste, 
etc.  Everything  of  any  kind  should  be 
cleaned  out  of  the  boiler  before  water  is  run 


•  :  .» ••       . >e  necessary  to  take 
\  ::•':£$  *Ke*3e\\trtand-hole   plates,    and   with  a 
small  hooked  rod  dislodge  everything  that  is 
loose  in  the  boiler. 

Spare  no  pains  in  this  work,  for  it  will  be 
labor  and  money  saved  in  future.  When 
the  boiler  is  thoroughly  clean  you  can  put  the 
plates  in  again,  but  before  doing  this  rub  the 
gaskets  thoroughly  with  plumbago,  and  they 
will  not  adhere  to  the  plate  where  exposed  to 
heat.  This  is  a  saving  of  time  and  gaskets  in 
breaking  joints  in  future.  The  old  way  of 
making  joints  upon  hand-hole  plates,  with 
hemp  gaskets  slushed  with  white  lead,  has 
gone  out  of  use,  having  been  superseded  by 
rubber  gaskets  made  for  the  purpose.  If  you 
are  remote  from  a  city,  however,  and  cannot 
get  a  rubber  gasket,  you  can  make  a  hemp 
gasket  which  will  answer  all  purposes.  Jute 
is  the  best  material  for  this  job  if  it  can  be  had, 
but  you  are  quite  as  likely  to  be  out  of  jute  as 
out  of  rubber  gaskets,  and  if  you  have  neither 
you  can  get  a  clothesline  most  anywhere. 
Unlay  this  and  take  the  twist  out  of  it ;  beat  it 
with  a  fiat  stick  so  as  to  reduce  it  to  its  original 
fiber  ;  then  braid  it  up  again  of  the  proper  size 
for  the  job  in  hand.  Find  the  right  length  for 
the  gasket,  and  join  the  ends  so  as  to  form  a 
ring  of  the  proper  size  that  will  fit  the  plate  ac- 


3 

curately  :  it  should  go  on  so  tight  that  you 
have  to  force  it  over  the  flange  of  the  plate. 
Cover  this  gasket  thoroughly  with  white  lead, 
and  then  put  it  in  its  place.  It  will  be  abso- 
lutely tight  if  the  work  has  been  properly  done. 

CLEANING  THE  BOILER. 

We  have  been  assuming  that  the  boiler  you 
have  taken  charge  of  is  a  new  one,  without 
scale,  but  it  it  is  an  old  one  there  is  likely  to  be 
a  quantity  of  scale  and  dirt,  which  must  be 
taken  out  at  once.  The  way  to  do  this  is  to 
us  the  best  tools  you  can  get  hold  of,  or  con- 
trive for  the  purpose.  The  place  to  look  for 
dirt  and  deposits  from  the  feed  water  is  in  the 
bottom  of  the  boiler  furthest  from  the  entrance 
of  the  feed  water,  and  in  the  parts  that  are  the 
coolest,  if  there  are  any,  when  the  steam  is  on. 
In  a  return  tubular  boiler  this  is  generally  in 
the  smoke-box  end,  which  is  not  so  hot  as  the 
fire-box  end;  the  quantity  of  rubbish  which  ac- 
cumulates in  a  neglected  boiler  is  astonishing, 
and  you  must  not  be  surprised  if  you  have  to 
remove  wheelbarrow  loads.  This  dirt  comes 
from  the  solid  matter  in  the  water,  both  that 
which  is  carried  in  mechanically  from  turbid 
supplies,  and  that  which  is  held  in  suspension 
until  set  free  by  heat.  Every  gallon  has  a  cer- 
tain amount,  and  as  many  gallons  are  evapor- 
ated daily,  unless  removed  weekly  it  soon 


makes  a  wheelbarrow  load.  This  dirt,  by 
backing  up  against  the  flue  sheet,  deprives  the 
ends  of  the  tubes  of  water*  which  not  only 
steals  part  of  the  heating  surface,  but  destroys 
the  ends  of  the  tubes  and  flue-sheet  by  corro- 
sion and  over  heating,  so  that  it  is  only  a  ques- 
tion of  time  when  the  boiler  will  be  practically 
useless.  If  the  lower  course  of  the  tube-ends 
in  the  smokebox  leak,  be  sure  that  they  have 
been  abused  in  the  manner  stated.  You  will 
probably  find  that  they  will  leak  after  dirt  has 
been  cleaned  out.  In  that  case  the  tubes  must 
be  re-expanded,  and  to  do  this  a  boiler  maker 
must  be  called  in.  Do  not,  upon  any  con- 
sideration, try  to  tinker  them  up  with  a  ham- 
mer yourself.  You  will  only  make  a  bad  mat- 
ter worse,  and  set  other  tubes  to  leaking  which 
were  tight.  Having  taken  out  what  may  be 
called  the  ''loose  dirt,"  though  some  ot  it  is 
very  far  from  being  loose,  you  will  find 
another  job  in  front  of  you,  and  that  is  to  get 
out  the  dirt  which  is  fast.  In  other  words,  the 
scale.  This  is  actual  stone,  .artificially  formed 
within  the  boiler  from  the  working  of  it.  It 
differs  in  character  with  the  kind  of  water 
used.  If  it  is  hard  water,  so-called,  it  will  be 
limestone  scale  ;  if  soft  water,  it  will  be  sul- 
phate of  magnesia  and  soda  scale  ;  either  one 
of  them  is  bad  enough,  so  far  as  the  boiler  is 


5 

concerned,  and  must  be  removed  absolutely  if 
there  is  to  be  any  economy. 

REMOVING  SCALE. 

There  is  a  way  to  do  this  which  we  have 
practiced  with  success,  and  that  is  to  run  the 
boiler  full  of  water  up  to  the  third  gauge  and 
then  put  in   a  quantity  of  a  scale  preventive. 
Of  these  there  are  numbers  in  market,  but  we 
do  not  name  any  one  as  the  best.     Doubtless 
none  of  them  are  wholly  useless,  though  some 
of  them  are  inert  or  do  not  act.     You  will  have 
to   find  out  by  experience  which  one   serves 
your    purpose.       Sometimes     caustic     potash 
answers  a  very  good  purpose.     This  when  the 
scale  is  chiefly  mud  with  sulphate  of  soda  and 
magnesia  combined.      Caustic   potash   is   the 
concentrated  lye  sold  in  grocery  stores,  but  if 
wanted  in  large  quantities  should  be  purchased 
of  wholesale  druggists.     To  use  it,  dissolve  it 
in  a  barrel  of  water,  say  40  pounds  to  the  bar- 
re],  and  pour  it  into  the  boiler.     This  is  about 
one-sixth  of  a  pound  of  potash  to  the  pound  of 
water,  and  is  strong  enough  for  the  purpose. 
After  the  purger  is  in  the  boiler  build  a  light 
fire  and  heat  the  water  to  boiling  point,  and 
then  haul  the  fire  and  let  the  contents  stand. 
It  is  better  to  do  this  on  Saturday  night,  if  pos- 
sible, leaving  the  water  in  the  boiler  until  Mon- 
day morning  ;  you  should  then  get  up   steam 


to,  say,  five  or  ten  pounds  pressure  on  the 
same  water,  haul  the  fire  all  out,  and  blow  the 
boiler  down.  You  will,  in  the  majority  of 
cases,  find  the  boiler  thoroughly  clean,  except 
for  chunks  of  scale  which  cannot  go  through 
the  blow-cock,  and  which  must  be  taken  out 
through  the  hand-holes. 

CAUTION. 

In  handling  caustic  potash  the  utmost  care 
must  be  used.  It  is  truly  caustic,  or  burning, 
and  if  a  portion  gets  in  the  eyes  it  will  cause 
serious  trouble.  The  same  is  true  of  sores  on 
the  hands.  Handle  it  with  gloves ;  treat  it 
very  respectfully. 


CHAPTER   II. 
USING  SCALE  PREVENTERS. 

If  caustic  potash  cannot  be  had,  a  substitute 
may  be  found,  in  rural  districts,  in  slippery 
elm  bark.  This  is  not  at  all  caustic,  but  quite 
the  reverse,  being  demulcent  in  character. 
How  it  acts  we  do  not  know  ;  but  that  it  has  a 
certain  efficiency  we  do  know,  because  we 
have  cleaned  boilers  thoroughly  with  it.  It 
makes  little  difference  how  much  is  used,  put 
it  in  the  boiler  and  let  it  stay  there  for  a  week, 
and  there  will  be  a  benefit  from  its  use. 

These  purgers  just  named  are  only  of  service 
where  the  scale  is  soft  ;  for  hard  scale  a  differ- 
ent one  must  be  used,  and  to  attack  lime  scale 
it  should  be  of  an  acid  character,  for  lime  is 
alkaline,  and  its  antidote  is  an  acid.  But  just 
here  trouble  is  likely  to  ensue  in  the  hands  of 
an  inexperienced  person.  A  good  many  will 
exclaim  loudly  against  using  an  acid  purger  in 
a  boiler,  arguing  that  it  will  destroy  the  boiler 
as  well,  and  that  very  soon.  Some  have  shown 
us  pieces  of  iron,  that  they  immersed  in  certain 
boiler  purgers,  that  were  badly  corroded.  This 
is  very  likely,  but  it  so  happens  that  no  boiler 
purger  is  used  in  that  way.  The  purger  is 
largely  diluted  with  water,  and  acts  very  slowly 
upon  the  iron.  It  attacks  the  scale  first,  be- 


cause  it  has  the  greatest  affinity,  or  liking,  for 
it ;  after  that  it  goes  for  the  boiler  plates  ;  but 
there  are  no  after  effects  ot  this  character  from 
a  boiler  purger,  because  it  is  no  longer  in  the 
boiler  when  the  scale  is  removed,  and  if  a 
boiler  is  thoroughly  washed  out  there  is  no 
danger  to  it  from  the  use  of  a  strong  purge. 
There  is  very  great  danger  from  the  presence 
of  heavy  lime  stone  scale,  and  since  nothing 
but  a  purger  with  an  acid  reaction  will  remove 
it,  we  do  not  fear  to  use  it  ourselves.  Some 
engineers  have  shown  us  boilers  from  which 
the  scale  was  removed  which  had  the  plates 
badly  corroded.  This  action  was  attributed  to 
the  use  of  the  purge,  when  it  was,  in  fact, 
caused  by  the  scale  itself.  The  corrosion  was 
going  on  all  the  time  underneath  the  scale,  and 
when  it  was  removed  the  injury  it  caused  was 
manifest.  Ot  two  evils  we  are  taught  to  choose 
the  least,  and  in  this  case  the  use  of  a  strong 
boiler  purger  is  less  than  the  injury  and  loss  of 
fuel  caused  by  scale.  Get  that  out  first, 
thoroughly  clean  the  boiler  after  of  all  traces 
of  the  purge,  and  there  will  be  no  trouble  aris- 
ing from  its  use.  It  is  understood,  of  course, 
that  alter  the  use  of  any  boiler  purge  that  the 
hand-hole  plates  must  be  taken  off  and  the 
boiler  cleaned  out  by  hand,  washed  with  a 
hose,  and  then  filled  up  and  blown  out  again 


before  steam  is  raised.  There  is  no  middle 
ground  or  half-way  measures  possible  in  deal- 
ing with  a  dirty  steam  boiler.  Get  down  to 
the  naked  iron  and  keep  it  so,  inside  and  out, 
and  the  boiler  twenty  years  old  will  steam  as 
freely  as  one  just  out  of  the  shop. 

OIL  IN  BOILERS. 

Do  not  upon  any  account  put  crude  oil  or 
any  other  kind  of  grease  in  a  steam  boiler.  It 
generally  gets  in  fast  enough  through  the 
feed  water  where  open  heaters  are  used, 
without  putting  it  in.  The  effect  of  putting 
oil  in  is,  in  a  great  many  cases,  to  cause  the 
crown  sheet  to  come  down,  or  the  lower 
sheets  to  bag.  When  first  put  in  the  oil  floats, 
but  it  gradually  picks  up  scum  from  the  sur- 
face, in  which  scum  there  is  always  more  or 
less  actual  mud  thrown  up  from  the  bottom  by 
the  boiling  water;  the  oil  then  becomes  like  tar, 
and  being  heavy  settles  on  the  plates  and 
sticks  fast.  Since  the  water  cannot  get  under- 
neath it  the  plates  are  overheated  and  come 
down,  notwithstanding  the  fact  that  there  is 
plenty  of  water  in  the  boiler.  Keep  every  kind 
of  grease  out  of  a  steam  boiler,  if  you  have 
to  filter  the  feed  water  to  do  it. 

BRACES  AND  STAYS. 

We  have  now  a  clean  boiler  to  deal   with ; 
let  us  see  in  what  condition  it   is  as  regards 


IO 

strength.     The  braces  are  the  first  to  be  con- 
sidered.     Perhaps  some  of  them  are    carried 
away  entirely;  such  a  state  of  things  is  by  no 
means  unknown.     They  must  be   replaced   at 
once  by  boiler  makers,    who   should   also  go 
over  every  other  pan  of  the  boiler  and  test  it 
for  condition  >  but  if  there  are  no  boiler  makers 
handy  the  engineer  must  do  it  himself.      The 
boiler   most  generally     used     is     the     return 
tubular,  which  is  a  plain  cylinder  with  an  ex- 
ternal fire-box,  from  which  the  heat  traverses 
the  bottom  and  enters  the  tubes  at  the  back, 
passing  through  them    to    the   breeching    and 
smoke-stack  in  front.     The  weak  point  in  the 
return  tubular  boiler  is  directly  over  the  bridge- 
wall,  where  the  heat  deflected  from  the  wall 
strikes  upon  the  shell.     This  spot  needs  to  be 
carefully  examined,  for  unless  the  boiler  has 
been  well  taken  care  of  it  wll  be  found    weak 
and  unsafe.     If  any  doubt  exists,    a  half  inch 
hole  should  be  drilled  in  the  bottom   to   ascer- 
tain the  exact  thickness  of  the  plate,   when,    if 
thinner  than  the  shell  elsewhere,    it  should  be 
removed,  and  a  new  plate   put  in.     The  sides 
of  the  boiler  should  also  be  examined  near  the 
wall,  or  where  the  boiler  meets  the  brick- work, 
for  here  there  is  often  trouble  from  corrosion  ; 
also    at  the  junction  of  the  blow-pipe  in  the 
bottom  or  at  the  end  of  the  boiler. 


II 


CHAPTER  III. 
MUD  DRUMS  AND  FEED-PIPE. 

If  there  is  a  mud-drum  attached  to  the  boil- 
er examine  it  very  thoroughly,  for  explosions 
of  mud-drums  are  very  common.  If  the  mud- 
drum  is  buried,  as  it  often  is,  it  is  probably 
corroded  greatly.  The  proper  place  for  a 
mud-drum  is  outside  of  the  boiler,  in  plain 
sight,  where  it  can  be  got  at  and  cleaned  out 
weekly.  The  object  of  it  is  to  catch  all  the  free 
mud,  so  to  call  it,  which  is  thrown  down  at 
night  when  the  boiler  is  not  running.  With 
some  water  used  for  steam  making,  as  on 
Western  rivers,  the  quantity  of  mud  so  de- 
posited is  very  large,  and  if  not  removed  it 
will  be  driven  back  into  the  boiler.  This  is 
particularly  true  where  the  feed  pipe  enters 
through  one  end  of  the  mud-drum.  It  does 
not  require  much  thought  to  see  that  this 
wholly  defeats  the  object  of  the  mud-drum,  for 
the  sediment  which  collects  over  night  is 
forced  through  the  boiler  again  at  the  first 
stroke  of  the  pump  in  the  morning. 

As  to  the  best  place  for  the  feedpipe  to  enter 
the  boiler  there  is  a  difference  of  opinion 
among  engineers,  but  there  is  no  doubt  but  that 
the  worst  place  is  through  the  mud-drum,  for  the 
reason  given.  Some  think  that  the  feed  should 


12 

enter  the  coolest  part;  some  put  it  in  the  steam 
space,  and  some  enter  it  at  the  front  end 
alongside  the  fire.  An  objection  to  this  is  the 
bad  effect  of  water  cooler  than  the  water  in 
the  boiler  upon  hot  plates;  an  advantage  is 
the  propulsion  of  any  sediment  that  may  lie 
upon  the  bottom  of  the  boiler  lo  the  back  end 
of  it,  where  there  is  no  trouble  in  removing  it; 
another  benefit  is  that  the  mechanical  action 
of  the  entering  jet  assists  the  circulation  by 
forcibly  driving  the  heated  water  from  the 
front  to  the  back,  and  replacing  it  with  cooler 
water,  but  to  effect  these  objects  the  feed  pipe 
must  project  within  the  boiler  for  a  few  inches 
so  as  to  give  what  we  shall  call  a  straight 
shot  from  it. 

BOILER  FITTINGS. 

In  these  are  included  every  sort  of  attach- 
ment to  a  boiler,  the  water  gauge,  gauge  cocks, 
safety  valve,  checks  of  all  kinds,  and  the  blow- 
off  valve  or  cock  for  blowing  the  water  out  of 
the  boiler.  This  last  is  a  much  more  important 
detail  than  it  is  generally  supposed  to  be,  and 
many  accidents  nave  happened  from  careless- 
ness with  it.  These  accidents  occurred  from 
"  sticking  "  any  sort  of  a  bent  pipe  (we  have 
actually  seen  an  old  leader  pipe  from  a  house 
used)  over  the  end  of  the  nipple  or  elbow  on 
the  blow-pipe.  The  blow-pipe  connection 


should  be  made  as  firmly  and  as  securely  as 
any  other  attachment  to  a  boiler.     If  one  re- 
flects for  a  moment,  it  is  easy  to  see  that  there 
is  a  tremendous  strain  on  a  pipe  which  is  dis- 
charging a  two  inch  stream  of  water  under  60 
or  70  pounds  pressure.     A  boiler  never  should 
be  blown  off  at  this  pressure,  but  it  sometimes 
has  to  be,  and  preparation  should  be  made  for 
it.     No  elbows  should  be  used  where  it  is  pos- 
sible to  avoid  them  ;  the  pipe  should  run   as 
straight  as  it  can  from  the  boiler  to  the  outer 
air,  and  if  a  cock  is  used  care   should  be  taken 
that  it  is  always  in  perfect  order.     It  should  not 
leak  a  drop  ;  the  bolt  at  bottom  which  keeps 
the  plug  in  the  cock  should  be  accurately  fitted, 
of  full  length,  entering  the  plug  not  less  than 
i%   inches,  and  have  a  good  head  on  it.     It 
must  never  be  meddled  with  or  touched,  except 
to   open   or   close   it,    wThen    under    pressure. 
Don't  hit  it  with  a  hammer,  either  on  the  under 
side  to  start  the  plug  up  if  it  sticks,    or  on  the 
top   for   any   purpose.     Remember  that   it   is 
under  pressure,  and  if  it  gives  way  it  is  almost 
certain  death  to  any  one  near  it.     Defer  all  tin- 
kering and  investigation  until  the  boiler  is  cold; 
or,  in  other  words,  make  everything  secure  be- 
fore steam  is  on;  then  there  will  be  no  trouble. 
Forethought,  care,  and  caution,  are  absolutely 
indispensable  qualifications  in  an  engineer,  and 


14 

it  is  useless  to  expect  success  or  ordinary 
economy  without  them.  No  man  can  be  an 
engineer  worthy  of  the  name  who  is  careless 
or  has  not  his  wits  about  him  at  all  times. 
Mr.  I-Didn't-Think  has  no  business  with  a 
steam  boiler. 

What  has  been  said  of  the  blow-cock  is  true 
of  all  the  other  fittings.  Every  one  of  them 
must  be  in  perfect  order  to  be  safe  and  efficient; 
an  engineer  must  bear  in  mind  that  he  is  deal- 
ing with  a  tremendous  agent,  which  is  safe 
only  when  in  its  place  and  under  control,  and 
every  gauge  or  fitting  of  every  kind  must  be 
securely  in  place  and  tight  of  itself,  that  is, 
tight  without  makeshifts  of  any  kind. 

The  safety  valve  in  particular  must  be  tight, 
for  a  great  deal  of  coal  can  be  lost  by  a  leaky 
valve.  It  should  be  free  and  clear  in  the  hoist, 
or  where  the  lever  is  to  be  raised — if  it  is  of  the 
lever  type — and  entirely  free  from  rust  in  all 
parts.  A  safety  valve  is  for  use,  not  for  emer- 
gency, and  if  it  is  not  in  order  it  will  not  act 
when  the  emergency  comes,  if  it  ever  does. 

It  is  not  every  engineer  that  can  do  the  work 
which  we  have  mentioned  with  his  own  hands, 
for  not  all  persons  in  charge  of  engines  are 
machinists;  these  instructions  convey  a  knowl- 
edge of  what  is  needed,  and  the  work  can  be 
supplied  by  those  competent  to  perform  it. 


CHAPTER  IV. 
GRATE  BARS  AND  TUBES. 

One  of  the  most  important  parts  of  a  boiler 
is  the  grate.  Curiously  enough  but  fe\v  give 
this  matter  sufficient  thought,  but  it  is  plain 
upon  reflection  that  the  air  \vhich  is  needed  to 
support  combustion  must  be  supplied  through 
it.  If  the  bars  are  warped  and  broken,  too 
much  air  goes  through  them,  with  the  effect  of 
wasting  fuel  or  checking  the  free  s'.eaming  of 
the  boiler.  Moreover,  a  broken  grate  bar  pre- 
vents proper  firing,  or  attention  to  the  fire  ;  all 
the  bars  should  be  in  good  order, 'with  no  open 
spaces  at  the  ends  (front  or  back)  or  sides.  As 
this  bears  directly  upon  the  subject  of  combus- 
tion, it  will  be  more  explicitly  alluded  to  fur- 
ther along  in  this  work. 

The  tubes  or  flues  particularly  demand  at- 
tention, and  must  be  absolutely  clean  inside 
and  out.  In  a  former  article  we  have  given 
directions  how  to  clean  them  outside — that  is, 
on  the  water  side,  but  they  must  be  clean  on 
the  fire  side  too.  With  anthracite  coal  this  is 
not  a  matter  of  difficulty,  but  with  soft  coal  it 
is  ;  not  so  much  through  the  soot  which  accu- 
mulates in  them  as  with  the  "  gurry,"  for  want 
of  a  better  name,  which  is  burned  on.  This 
last  is  the  tarry  distillates  of  the  coal,  or  heavier 


i6 

products  of  combustion,  which  are  condensed 
on  the  inside  of  the  tubes  when  the  boiler  is 
comparatively  cold,  or  in  getting  up  steam 
every  morning,  and  is  by  no  means  easy  to 
remove.  It  not  only  checks  steam  making  by 
obstructing  the  heat  from  passing  through  the 
tubes,  but  it  hinders  the  draught  by  the  ad- 
herence of  soot  and  roughening  the  surface  of 
the  tubes.  It  would  seem  that  the  fire  should 
burn  this  deposit  off,  but  it  requires  a  much 
higher  temperature  to  do  this  than  that  in  the 
tubes,  and  the  only  way  to  remove  it  when  it 
has  accumulated  in  quantity  is  to  thoroughly 
slush  the  tubes  with  crude  petroleum  oil,  ap- 
plied with  a  swab  and  allowed  to  remain  for  a 
day  or  so,  when  it  should  be  swabbed  out 
again.  This  is  a  job  which  but  few  persons 
care  to  undertake,  particularly  if  the  boiler  is 
large,  but  in  some  cases  it  becomes  neccessary. 
Crude  petroleum  is  a  solvent  for  tar,  and  will 
clean  the  tubes  thoroughly. 

Of  course  it  has  to  be  undertaken  in  holiday 
time,  when  the  boiler  is  idle  for  a  day  or  two, 
for  to  be  of  any  service  the  oil  must  remain  in 
the  tubes  at  least  24  hours.  It  is  of  no  use  to 
try  to  rasp  this  "  gurry"  out  with  steel  brushes- 
or  scrapers.  It  is  as  tough  as  India-rubber  and 
a  scraper  slides  over  it. 


BRIDGE  WALLS. 

The  bridge  wall  in  a  boiler  is  intended  to 
delay  the  products  of  combustion  in  the  fire- 
box as  long  as  possible,  and  to  confine  the 
heat  from  the  fire  within  the  area  of  the  grate. 
To  do  this  it  is  manifest  that  the  throat,  or 
opening  over  the  bridge  wall,  between  the  top 
of  it  and  the  boiler,  should  be  as  small  as  it 
can  be,  and  leave  room  enough  for  a  good 
"draught,"  so-called.  There  is,  however,  a 
danger  in  this,  and  this  danger  is  that  if  the 
throat  is  too  narrow,  the  heat,  and  sometimes 
the  flame,  is  sharply  deflected  and  concentrated 
directly  upon  one  spot  over  the  wall.  The 
result  of  this  is  that  the  sheet  for  a  foot  or  so  is 
fire-eaten,  or  thinned  and  weakened ;  it  is 
burned,  as  boiler  makers  would  say,  notwith- 
standing there  may  have  been  plenty  of  water 
in  the  boiler.  The  opening  over  the  bridge 
wall  should  never  exceed  ten  inches,  nor  be 
less  than  eight  inches,  and  it  should  follow 
the  curve  of  the  boiler.  There  are  a  great 
many  patents  on  bridge  walls  which  are  in- 
tended to  improve  the  combustion  by  admit- 
ting air  over  them,  or  through  them,  but  never 
having  had  any  experience  with  them  we  can- 
not say  anything  about  them. 

Assuming  that  the  boiler  has  been  put  in 
good  condition,  we  will  look  at  the  engine. 


i8 

The  hints  given  in  the  previous  chapters 
should  enable  any  intelligent  man  who  is  fit 
to  be  about  a  steam  plant,  to  have  a  boiler 
which  will  steam  freely  and  as  economically 
as  its  construction  will  allow.  A  treatise 
could  be  written  upon  boilers  alone,  and  many 
such  works  are  in  existence.  The  contents, 
however,  relate  more  particularly  to  the  con- 
struction, a  matter  which  does  not  enter  into 
an  engineers  duties. 

THE  SLIDE-VALVE  THROTTLING  ENGINE. 
The  commonest  form  of  steam  engine  in  use 
to-day  is  the  slide-valve  throttling  engine, 
which  is  regulated  by  governors  of  various 
kinds.  It  is  the  simplest  of  machines,  easily 
managed  by  any  one  after  a  little  instruction, 
and  frequently  is  found  in  charge  of  men  and 
boys  who  have  had  no  experience  whatever, 
they  merely  knowing  that  a  certain  valve  has 
to  be  opened,  and  that  the  engine  must  be  at 
half-stroke  to  start.  Such  persons  are  not  en- 
gineers in  any  sense  of  the  word,  for  they  do 
not  intend  to  follow  the  business  any  longer 
than  they  can  help.  Our  instructions  are  not 
directed  to  them,  but  to  intelligent  young  men 
who  have  started  with  the  intention  of  learning 
all  that  they  can.  The  first  thing  to  do  then  in 
taking  charge  of  an  engine  is  to  see  in  what 
condition  it  has  been  handed  over,  in  order  that 


19 

you  may  not  be  blamed  for  the  sins  of  those 
who  preceded  you.  The  cylinder  is  the  seat  of 
power,  and  we  want  to  examine  it  as  soon  as 
we  can  get  a  chance.  If  we  have  been  under 
steam  the  day  before,  we  leave  the  engine  on 
the  back  center  at  night  (Saturday  night  foi 
instance),  and  take  off  the  cylinder  head.  The 
piston  is  then  at  the  end  of  its  stroke,  and  we 
have  an  opportunity  to  see  what  the  clearance 
is  between  the  piston  and  the  cylinder  head. 
The  latter  detail  will  leave  its  mark  on  the 
cylinder  after  it  is  taken  out,  so  it  will  be  easy 
to  measure  directly  from  the  piston  to  the  said 
mark.  Some  clearance  is  necssary  for  safe 
working,  but  it  should  be  just  as  little  as  pos- 
sible; clearance  is  waste  room  that  has  to  be 
filled  with  live  steam  at  every  stroke  before 
any  work  is  done  on  the  piston. 

As  a  rule  excessive  clearance  is  given  in 
small  engines,  for  no  reason  whatever,  except 
that  some  builders  appear  to  think  that  there  is 
less  danger  of  breaking  down.  Suppose  that 
the  cylinder  is  12  inches  diameter:  then  the 
p;ston  should  run  within  one-quarter  of  an 
inch  of  the  head.  If  the  piston  is  of  that  class 
where  the  follower  bolts  stick  out  the  depths  of 
their  heads,  it  cannot  run  so  close  as  this,  and 
probably  there  is  an  inch  or  more  clearance 
in  such  a  cylinder,  but  it  is  easy  to  reduce  the 


20 

clearance  in  such  cases  to  the  lowest  point, 
and  this  is  easily  done  by  taking-  the  follower 
to  a  machine  shop  and  having  the  bolt  holes 
counterbored,  so  as  to  let  the  heads  in  as  far  as 
possible;  having  done  this,  fill  up  on  the  head 
itself  by  bolting  on  a  cast-iron  plate  of  the  re- 
quired thickness,  cutting  out  where  it  covers 
the  steam  port.  The  reduction  of  clearance 
often  makes  a  boiler  much  larger;  or,  in  plainer 
terms,  since  less  waste  occurs  it  is  easier  to 
keep  steam  on  a  boiler  than  when  the  clear- 
ance is  excessive.  Having  found  what  the 
clearance  is  on  the  back  end  then,  we  discon- 
nect the  piston  from  the  cross-head,  and  (run- 
ning the  crank  on  the  forward  center),  we 
find  what  it  is  on  the  front  end.  This  we  do 
by  shoving  the  piston  clear  up  against  the  for- 
ward head.  Having  done  this  we  measure 
from  the  follower  back  to  the  end  of  the  stroke, 
as  shown  by  the  wear  on  the  guides,  and  the 
wear  on  the  cylinder  itself.  If  this  measure- 
ment is  half  an  inch  longer  than  the  working 
stroke  of  the  piston,  there  is  half  an  inch 
clearance  on  the  front  end,  and  as  there  are  no 
follower  bolts  on  that  end  it  is  all  waste,  ex- 
cept so  much  as  is  actually  needed  for  the  safe 
wording  of  the  engine.  We  should,  if  the  en- 
gine was  ours,  reduce  this  clearance  also,  to 
the  same  degree  that  we  did  the  back  end,  but 


21 

as  it  entails  more  or  less  work  for  the  shop,  it 
will  be  as  well  to  leave  the  clearance  half  an 
inch  on  the  front  end;  if  the  clearance  is  one 
inch,  however,  no  consideration  of  trouble  or 
expense  should  be  spared  to  reduce  it  in  the 
same  way  that  we  fixed  the  back  head,  by 
adding-  to  the  head  itself.  The  clearance  in 
any  engine  must  be  reduced  to  its  lowest 
terms,  for  by  doing  this,  if  the  engine  is  yours, 
you  put  money  in  your  pocket;  if  it  belongs  to 
some  one  else  and  you  are  in  charge  of  it,  you 
get  the  credit  of  making  a  saving,  and  this  will 
be  a  feather  in  ycur  cap  worth  working  for. 


22 


CHAPTER  V. 

THE  PISTON. 

Now  that  we  have  the  clearance  matter  at- 
tended to,  let  us  see  what  kind  of  a  looking 
thing1  we  have  for  a  piston.  This  detail  of  a 
steam  engine  is  of  all  conceivable  forms — and 
some  inconceivable  forms,  to  any  one  who 
thinks  what  a  piston  has  to  do.  They  are 
made  as  heavy  as  hydraulic  plungers,  and  with 
as  many  attachments  as  possible,  in  the  shape 
of  rings,  with  springs  to  keep  the  rings  out  to 
the  cylinder,  and  screws  in  the  springs  to  keep 
the  springs  out  to  the  rings.  The  reason  that 
some  firms  make  them  in  this  way  is  because 
their  grandfathers  made  them  so,  and  that  is 
reason  enough  in  their  eyes.  If  the  piston 
you  have  taken  out  is  of  this  class  it  is  your 
and  the  owner's  misfortune,  but  as  we  are  not 
giving  instructions  upon  how  to  build  engines, 
we  will  merely  state  how  this  old-fashioned 
piston  is  to  be  put  in  as  good  condition  as  pos- 
sible. Pistons  are  liable  to  become  leaky  in 
the  following  places  :  between  their  flanges 
where  the  rings  bear;  between  the  rings  and 
the  cylinder  itself;  through  the  follower  into 
the  body  of  the  piston.  Wherever  there  is  a 
joint  look  for  a  leak,  for  joints  become  imper- 
fect through  use  and  time.  If  the  rings  move 


23 

back  and  forth  between  the  nanges  of  the 
piston  they  leak,  and  must  be  made  tight  by 
skinning  off  the  follower.  This  is  of  course  a 
shop  job,  with  which  the  engineer  has  nothing 
to  do,  but  before  the  piston  is  sent  to  the  shop 
for  repairs  the  engineer  should  be  sure  that  the 
piston  needs  it.  Very  often  it  will  be  found 
by  examination  that  dirt  or  "  burrs  "  have  got 
in  betwreen  the  follower  and  the  spider,  or  else 
the  thread  on  the  bolt-holes  in  the  spider  has 
been  raised  around  the  edges,  so  that  the  fol^ 
lower  will  not  go  down,  iron  and  iron.  An 
experienced  engineer  will  soon  find  out 
whether  these  things  have  happened  by  taking 
a  smooth  file  and  going  carefully  over  the  fol- 
lower-seat on  the  spider,  or  main  casting  of 
the  piston.  In  this  way  he  will  find  all  the 
burrs  or  bruises  that  have  raised  the  surface, 
and  dress  them  off  level  ;  then  when  he  puts 
the  follower  on  again  and  screws  it  up  solid 
without  the  rings  in,  he  should  take  a  hammer 
and  strike  on  the  outside  of  the  follower 
opposite  solid  iron.  If  the  follower  is  tight  on 
its  seat  it  will  sound  like  striking  on  an  anvil ; 
if  it  is  leaky  the  sound  given  out  will  be  like 
striking  a  piece  of  iron  lying  on  an  anvil. 
Leaks  can  also  be  told  by  the  appearance  of 
the  parts,  but  as  this  is  not  easily  conveyed  in 
print  we  shall  not  attempt  it.  The  best  way 


24 

in  all  cases  is  to  send  the  piston  to  a  good 
machine  shop  and  have  it  put  in  perfect  order, 
and  this  is  why  it  was  taken  out  the  first  thing-, 
so  that  it  might  be  going  forward  while  we  are 
dismantling  other  parts  of  the  engine. 

THE  SLIDE  VALVE. 

The  next  thing  we  do  to  ascertain  the  condi- 
tion of  our  engine  is  to  take  the  bonnet  off  the 
steam  chest  and  see  in  what  shape  the  valve 
and  its  seat  are.  An  inexperienced  man  is  very 
likely  to  get  into  trouble  here,  and  do  damage 
to  the  engine.  Bolts  and  nuts  which  have  been 
long  undisturbed  are  very  hard  to  start,  and  in 
very  many  cases  they  either  break  short  off  in 
the  casting,  or  else,  in  the  case  of  stud  bolts, 
come  away  at  the  bottom,  and  unscrew  from 
the  casting.  Either  of  these  misfortunes  is 
bad,  because  it  is  not  an  easy  task  to  get  out  a 
broken  stud  bolt,  or  to  make  one  tight  in  its 
seat  after  it  has  been  forcibly  removed ;  there- 
fore, if  the  nuts  do  not  yield  to  moderate  force 
exerted  on  a  wrench,  pour  a  little  kerosene  on 
them  and  let  them  stand  half  an  hour.  Kero- 
sene is  the  most  pervasive  fluid  known  to  the 
trade,  and  it  will  seep  into  the  most  minute 
crevices;  if  after  its  application  the  nuts  will 
not  then  start,  get  an  iron  ring,  or  a  big  nut 
with  some  body  of  metal  in  it  and  heat  it  red 
hot.  Put  this  over  the  stubborn  nut  until  it  has 


25 

become  very  warm  and  it  will  come  away 
without  any  trouble. 

If  we  digress  here  for  a  moment  it  is  because 
the  occasion  seems  to  demand  it.  This  digres- 
sion is  to  again  insist  upon  the  necessity  of 
care  and  caution  in  dealing  with  a  steam  en- 
gine. It  is  no  evidence  of  skill  for  a  man  to 
go  at  a  steam  engine  with  a  hammer  and 
wrench  and  slaughter  right  and  left,  for  by  pur- 
suing this  course  he  can  do  more  damage  in  a 
moment  than  he  can  repair  in  a  day,  and  he 
can  save  both  time  and  money  by  going  at 
every  job  in  a  workmanlike  manner. 

The  slide  valve  is  really  the  heart  of  the 
steam  engine,  for  upon  its  perfect  condition 
and  perfect  action  everything  depends  ;  if  it  is 
off  its  seat  or  badly  set  there  can  be  no  econ- 
omy. When  we  take  up  a  slide  valve  in  an 
old  engine  we  shall,  in  nine  cases  out  of  ten, 
find  it  in  very  bad  condition.  This  is  owing, 
in  a  great  measure,  to  the  way  in  which  it  is 
connected  to  the  mechanism  that  operates  it, 
and  to  the  way  in  which  it  is  constructed. 
Most  slide  valves  are  extremely  faulty  in  this 
respect.  In  order  to  keep  the  steam  chest  as 
short  as  possible,  the  valve  seat  is  made  short, 
and  very  often  the  valve  overruns  the  seat,  so 
as  not  to  wear  a  shoulder  on  it.  The  valve 
stem,  acting  on  the  stuffing-box  as  a  fulcrum, 


26 

tends  to  pry  the  valve  off  its  seat,  notwith- 
standing the  pressure  upon  it,  with  the  result 
that  the  face  of  the  valve  is  worn  rounding  in 
the  direction  of  its  stroke.  Where  this  is  the 
case  it  must  necessarily  leak,  for  a  slide  valve 
seat  is  like  the  slide  valve  itself — if  one  is 
rounding  the  other  must  be  hollow,  in  some  de- 
gree, unless  it  is  very  much  harder  than  the 
valve  itself.  The  time  to  test  a  valve  for  leaks 
is  when  the  engine  is  running,  and  it  can  be 
told  very  quickly  by  watching  the  exhaust 
where  it  can  be  seen.  If  this  is  sharp  and 
clear  at  every  stroke  the  valve  is  tight,  but  if  it 
is  followed  by  a  secondary  jet  that  scarcely 
clears  the  exhaust  pipe,  the  valve  or  the  pis- 
ton leaks,  and  quite  likely  both  ;  any  leak 
through  the  piston  would  also  show  on  the  ex- 
haust, but  in  this  case,  unless  the  piston  leaks 
very  badly  indeed,  it  is  likely  to  be  a  leak  of 
the  valve  which  shows  on  the  exhaust.  To 
test  it  for  condition,  obtain  a  straight  edge  and 
lay  it  across.  Hold  the  straight  edge  absolute- 
ly vertical,  not  tipped  to  one  side,  and  it  will 
soon  show  in  what  condition  the  valve  and  the 
seat  are.  The  remedy  for  a  leaky  slide  valve 
is  in  the  machine  shop. 


27 

CHAPTER  VI. 
TESTING  THE  VALVE  WITH  RELATION  TO  THE  PORTS. 

To  find  out  whether  the  valve  is  properly 
made  in  the  first  instance,  or  whether  it  has 
been  tampered  with  by  some  engineer  in 
charge  before  you,  proceed  as  follows  : — Take 
a  sheet  of  paper  large  enough  to  entirely  cover 
the  valve  seat  and  lay  it  on  it.  Rub  all  over 
the  edges  of  the  ports  so  as  to  obtain  a  fac 


Fig.  i. 

simile  of  them.  Then  get  a  piece  of  pine  half 
an  inch  thick  and  three  inches  wide,  and  put 
the  edge  of  it  on  the  diagram,  transferring  the 
ports  to  the  stick,  thus : — Do  the  same  to  the 
valve,  and  you  will  have  a  fac  simile  of  the 
valve  and  its  ports,  which  can  be  more  readily 
handled  than  by  taking  the  valve  itself,  which 
is  heavy  and  hard  to  see  distinctly  when  in 
the  chest.  Now  these  directions  sound  very 
simple,  and  are  very  easy  to  understand  by 


28 

one  who  knows  all  about  the  matter  before- 
hand, and  who  knows  what  he  expects  to  see, 
but  they  are  not  so  simple  to  a  young-  man 
who  reads  them  for  the  first  time,  or  who  is 
unacquainted  with  the  action  of  a  slide  valve, 
and  it  is  mainly  to  readers  of  this  class  that 
this  work  is  addressed.  But  we  will  try  to 
make  it  as  simple  as  possible,  and  so  that  any- 
one without  previous  knowledge  of  a  slide 
valve  can  see  at  a  glance  whether  it  is  properly 


Fig.  2. 

made  or  not  Actual  comparison  of  the  valve 
and  valve  seat  templets  will  appear  further  on. 
Let  us  say,  however,  that  there  are  slide 
valves  of  many  kinds,  flat  faced,  round  faced 
(as  in  the  case  of  a  piston  slide-valve),  V  faced, 
etc.;  but  in  this  article,  when  we  say  slide 
valve  we  refer  especially  to  the  common  cast- 
iron  box  without  a  bottom,  which  is  generally 
used  in  engines,  as  shown  in  the  engraving, 
fig.  2.  This  covers  both  ports  and  extends 
some  distance  over  them  on  each  side.  That 


29 

is  to  say,  the  end  of  the  valve  laps  over  the 
ports,  and  the  part  projecting  is  called  the  lap 
of  the  valve.  The  cavity  inside  the  valve  is 
the  exhaust  port  of  the  valve,  and  this  also  laps 
over  the  exhaust  edge  of  the  steam  port  some- 
times ;  the  outside  lap  is  called  steam  lap,  or 
lap  on  the  steam  side,  and  the  inside  lap  is 
called  exhaust  lap — when  there  is  any.  Usually 
the  exhaust  port  in  the  valve  coincides  with 
the  inside  edges  of  the  steam  ports  as  shown  in 


Steam  lap 


Exhaust  port  of  value 
/  line  and  line  exhaust  "\ 


Exhaust  port 
mjjf  of  value  face 


Fig.  3. 

fig.  3,  and  when  in  this  condition  it  is  said  to 
have  line  and  line  exhaust.  Sometimes  the 
exhaust  is  given  clearance  ;  that  is  to  say,  the 
steam  port  on  the  exhaust  side  is  open  slightly, 
and  when  in  this  condition  it  is  said  to  have 
exhaust  lead,  or  lead  on  the  exhaust  side.  A 
slide  valve  then,  works  normally,  that  is  to 
say  naturally,  under  these  conditions  :  It  is  a 
cast-iron  box  covering  both  ports  all  round,  so 
that  no  steam  can  get  into  the  cylinder  unless 


30 

the  valve  is  moved  so  as  to  expose  one  of  the 
ports.  To  recapitulate  :  the  part  which  projects 
over  the  ports  is  called  steam  lap  ;  the  inside 
cavity  of  the  valve  is  the  exhaust  port ;  the 
inside  edge  of  the  steam  port  is  the  exhaust 
side  ;  the  outside  end  of  the  valve  is  the  steam 
side;  and  the  same  on  both  sides  of  course. 
These  details  are,  naturally,  familiar  enough  to 
experienced  engineers,  but  we  must  not  forget 
that  there  are  young  men  coming  into  the  trade 
continually  who  have  all  their  trade  before 
them,  and  who  have  it  to  learn  as  we  had  to, 
and  it  is  for  them  that  these  explanations  are 
given.  Let  us  now  look  at  the  action  of  the 
valve. 

DEFECTS  OF  THE  SLIDE  VALVE. 

Were  it  not  for  one  inherent,  and  we  may  say, 
hereditary  defect,  the  slide  valve  would  be  the 
ideal  one  for  its  purpose,  for  all  the  functions 
are  performed  by  one  valve.  This  defect  is 
that  it  is  limited  in  its  application  to  working 
steam  expansively.  As  will  be  readily  seen 
by  anyone  who  uses  the  templet,  fig.  i,  where 
the  valve  face  is  shown  in  section,  when  it  is 
applied  to  the  valve  and  moved  to  the  various 
positions  of  opening  and  closing  the  valve,  the 
exhaust  is  more  or  less  throttled  or  choked;  its 
area  is  greatly  reduced,  so  that  escape  of  the 
exhaust  is  delayed.  The  result  of  this  is  that 


the  exhaust  steam  presses  back  on  the  piston 
(back  pressure  so-called),  and  takes  away  just 
so  much  from  the  power  of  the  live  steam  on 
the  other  side  which  is  driving  the  piston  for- 
ward. This  back  pressure  varies  in  amount 
with  the  position  of  the  valve  and  the  point  of 
the  piston  stroke  at  which  the  valve  closes. 
For  instance,  in  plain  words,  when  a  slide 
valve  cuts  off  at  three-quarters  of  the  piston 
stroke  there  should  be  little  or  no  back  pressure 
in  a  properly  constructed  valve,  for  the  exhaust 
is  open  long  enough  to  allow  all  the  dead  steam 
to  escape,  but  at  points  of  the  piston  stroke 
under  three-quarters  the  exhaust  is  not  free, 
and  a  cut-off  obtained  with  a  common  slide 
valve  under  five-eighths  of  the  piston  stroke  has 
to  be  paid  for  by  loss  of  live  steam  pressure. 
Notwithstanding  this  fact  there  are  many  slide 
valves  cutting  off  to-day  at  one-half  of  the 
stroke,  and  under  that  at  times,  and  the  de- 
signers of  them  are  satisfied — that  is  to  say, 
they  have  to  be  satisfied — for  the  common  slide 
valve  will  always  create  undue  back  pressure 
at  points  under  eleven-sixteenths  of  the  piston 
stroke.  This  is  shown  very  plainly  by  indi- 
cator cards,  where  the  last  part  of  the  exhaust 
is  caught  in  the  cylinder  by  the  piston  and 
pushed  uphill,  if  we  may  so  express  it,  until 
(when  nearly  on  the  center)  there  is  a  pressure 


32 

opposed  to  the  piston  closely  approximating 
boiler  pressure.  Whether  this  is  economy  or 
not  every  one  must  judge  for  themselves.  To 
expend  live  steam  pressure  and  power  stored 
in  the  flywheel  in  trying  to  make  dead  steam 
alive,  by  squeezing  it  between  the  piston  and 
cylinder  head,  always  seemed  to  us  unwise, 
for  the  reason  that  we  do  not  get  back  as  much 
work  from  the  imprisoned  steam  as  we  spent 
to  catch  it,  but  as  it  is  no  part  of  our  intention 
to  discuss  moot  points  or  theories  in  this  sedes, 
we  go  no  further  in  this  direction. 


33 


CHAPTER  VII. 
LAP  AND  LEAD. 

The  object  of  putting-  lap  on  a  slide  valve  is  to 
cut  off  the  steam  early  in  the  stroke  of  the 
piston.  Suppose  the  steam  end  of  the  valve 
had  no  lap  at  all,  but  barely  covered  the  steam 
port:  then  so  soon  as  the  piston  moved  the 
valve  would  open  and  continue  opening,  clos- 
ing barely  in  time  to  open  again  for  the  return 
stroke  of  the  piston.  Now  suppose  we  add 
one-quarter  of  an  inch  lap  to  the  valve ;  then 
the  valve  would  open  just  as  soon  as  it  did  be- 
fore, because  we  have  advanced  the  eccentric 
to  permit  it  to  open,  but  it  would  close  sooner 
by  the  amount  of  the  lap,  because  we  have 
stolen,  so  to  speak,  a  quarter  of  an  inch  from 
the  travel  of  the  valve  by  advancing  the  eccen- 
tric ;  therefore,  if  it  closes  sooner  it  cuts  off  the 
live  steam  earlier  in  the  stroke;  but,  as  ex- 
plained previously,  it  cuts  off  the  exhaust  also. 
We  introduce  this  as  an  illustration  of  the 
uses  of  lap.  Laps  on  slide  valves  vary  all  the 
way  from  half  an  inch  upon  a  twenty-five 
horse-power  engine  to  one  inch  and  upward 
on  high  power  engines  ;  on  very  large  marine 
engines  the  lap  amounts  to  3"  sometimes  ;  on 
locomotives  it  is  usually  one  inch.  If  you 
have  aii  engine  which  "takes  steam  all  the 
3 


34 

way,"  that  is,  works  full  stroke,  you  can 
materially  increase  its  economy,  and  to  some 
extent  its  power,  by  adding  lap  to  the  valve 
upon  the  steam  side  ;  the  amount  of  it  cannot 
be  stated  definitely,  but  must  be  governed  by 
the  size  of  the  engine.  Lead  on  a  slide  valve 
is  the  amount  that  the  port  is  open  to  admit 
steam  when  the  engine  is  on  the  dead  center. 
The  object  of  lead  is  two-fold:  to  have  the 
ports  and  cylinder  full  of  live  steam  the  instant 
that  the  return  stroke  begins,  and  to  check  the 
momentum  of  the  parts  as  they  turn  the  center, 
or  change  the  direction  of  motion.  Now  both 
the  lap  and  the  lead  of  a  valve  have  an  intimate 
relation  to  setting  the  valve  for  the  distribution 
of  steam,  and  as  this  will  be  alluded  to  further  on 
in  this  series,  we  will  say  no  more  under  these 
heads,  because  we  shall  be  obliged  to  traverse 
the  same  ground,  and  this  involves  tiresome 
repetitions. 

THE  PRESSURE  ON  A  SLIDE  VALVE. 
Another  defect  or  objection  to  a  slide  valve  is 
the  pressure  upon  it  and  the  power  required  to 
drive  it.  This  is  great,  though  it  is  not  so 
large  as  it  is  generally  supposed  to  be.  Spe- 
cifically, in  the  case  of  small  steam  engines, 
Mr.  C.  Giddings,  of  Massillon,  Ohio,  made  a 
dynamometer  for  the  purpose  of  ascertaining 
the  power  required  to  move  the  valve  on  a 


35 

6^4"  X  IQ"  horizontal  engine.  The  surfaces 
were  not  given  nor  the  pressures,  but  when 
exerting  13.5  horse-power  at  200  revs,  per 
minute,  the  power  expended  in  working  the 
valve  was  one-fifth  of  one  horse-power.  In  an 
engine  of  9"  cyl.  X  12"  stroke,  with  a  three- 
ported  flat  slide  valve,  at  100  revs,  of  engine 
per  minute,  the  power  required  to  drive  the 
valve  was  7.3  per  cent,  of  the  power  developed 
by  the  engine,  which  last  was  n.  i  h.  p.  With 
a  balanced  slide  valve  on  the  same  engine,  at 
100  revs.,  developing  15.6  h.  p.,  the  percentage 
of  load  on  the  valve  stem  was  only  i  per  cent, 
{Mechanical  Engineer,  page  62,  vol»  12,  1886). 
This  adduces  an  argument  in  favor  of  balanced 
valves  vs.  plain  valves  ;  that  is  to  say,  the  one 
is  6.  i  per  cent,  lighter  than  the  other  to  drive, 
but  the  fact  remains  that  without  any  balanc- 
ing but  7  per  cent,  of  the  power  of  the  engine 
was  required  to  drive  it  in  a  small  engine.  We 
do  not  say  that  this  is  not  serious,  nor  do  we 
think  it  unworthy  of  notice,  but  the  fact  re- 
mains that  some  valves  require  less  pressure 
to  work  than  others,  owing  to  the  manner  in 
which  they  are  lubricated  and  the  condition  of 
the  seats.  This  last  is  the  point  we  wish  to 
make,  for  if  the  seat  is  cut  the  power  required 
will  be  much  greater  than  if  it  was  in  good 
order.  Moreover,  if  the  metal  of  the  valve  and 


36 

seat  are  of  the  same  degree  of  hardness,  the 
valve  will  not  work  so  well  as  when  one  is 
harder  than  the  other.  Of  course  the  valve 
should  be  the  softest,  for  it  is  easy  to  replace 
or  re-face,  while  the  seat  is  difficult  to  get  at. 
The  pressure  on  top  of  a  slide  valve  is  the  steam 
in  the  chest  bearing  it  down.  When  the  en- 
gine is  at  work  there  is  a  pressure  beneath  the 
valve,  reacting  on  the  under  side  of  its  face, 
for  the  area  of  the  port  and  through  it.  There 
is  also  a  back  pressure  from  the  exhaust  steam 
passing  through  the  exhaust  port  of  the  valve ; 
both  of  these  pressures  tend  to  reduce  the 
direct  pressure  on  the  back  of  the  valve,  but  to 
what  extent  can  only  be  told  by  recording  the 
facts  in  some  particular  case.  The  mean  effec- 
tive pressure  shown  by  cards,  as  existing  in 
the  cylinder,  is  the  pressure  acting  on  the  port- 
area  face  of  the  slide  valve. 

STEM  CONNECTIONS  TO  THE  VALVE. 
We  have  said  previously  that  one  defect  of 
the  slide  valve  was  its  liability  to  wear  untrue. 
One  great  cause  of  this  is  the  manner  in  which 
the  stem  is  connected  to  the  valve  itself.  In 
locomotives  the  yoke  is  used  exclusively.  We 
believe  there  is  not  a  single  modern  locomo- 
tive built  without  it,  the  reason  being  that  there 
are  no  nuts  or  other  details  to  work  loose  in- 
side the  chest. 


37 

This  is  of  the  greatest  importance  in  an  en- 
gine which  is  worked  hard  under  high  press-ure 
constantly,  but  the  yoke  has  its  defects  as  well 
as  all  other  mechanical  devices.  It  frequently 
breaks,  and  at  times  cramps  the  valve  so  that 
it  does  not  seat  squarely  ;  it  cannot  be  got  out 


Fig.  4. 

without  lifting  the  steam  chest,  and  it  is  also 
very  heavy,  and  unless  supported  by  the  valve 
itself,  wears  away  the  gland  very  rapidly. 
Other  common  connections  to  valves  are  the 
nut  in  a  pocket  on  the  back,  four  nuts  on  a 
straight  stem,  the  latter  being  run  through  a 
hole  in  the  back  of  the  valve,  as  shown  in  fig. 
5 ;  T  heads  on  the  stem  are  also  common,  the 
T  fitting  in  a  cross  in  the  back  of  the  valve. 
The  nut  in  a  pocket  connection  is  one  which  is 
very  liable  to  give  trouble  to  engineers,  for  it 
is  easy  to  see,  unless  the  nut  is  exactly  at  right 


angles  to  the  travel  of  the  valve,  that  it  is  apt 
to  cramp  the  valve  and  keep  it  off  i  s  seat.  As 
the  stem  is  constantly  wearing  down  the 
trouble  is  of  frequent  occurrence,  and  it  is  diffi- 
cult to  detect  when  the  engine  is  cold,  for  the 
reason  that  the  valve  appears  to  be  solid  on  its 


Nut 


Figs.  5  and  6. 

seat.  We  have  seen  engines  which  refused 
work  simply  from  this  connection  to  the  valve. 
Upon  opening  the  throttle  the  engine  would  get 
steam  under  the  valve  and  through  both  ports, 
and  nothing  but  easing  the  nut  in  the  pocket 
would  let  the  valve  down  solid.  Fig.  5  is  the 


39 

nut  and  pocket  connection,  and  the  nut  should 
in  all  cases  be  faced  rounding  on  the  working 
faces.  A  far  better  and  simpler  modification 
of  this  plan,  and  one  we  have  used  with  suc- 
cess, is  shown  in  fig.  6;  it  never  fouls,  and  the 
nut  allows  the  valve  system  to  be  lengthened 
or  shortened  without  the  use  of  jam  nuts.  It  is 
easily  put  in  or  taken  out,  and  fills  all  the  re- 
quirements. 

The  solid  nut  arrangement  shown  is,  to  our 
way  of  thinking,  the  best.  It  holds  firmly  if 
properly  fitted  up,  and  it  is  also  cheap  to  make, 
being  all  lathe  work.  It  never  cocks  the  valve 
or  binds  it  any  way  ;  take  it  all  in  all,  it  is  hard 
to  find  one  better.  These  connections  are  the 
ones  that  are  most  commonly  met  with,  and  it 
is  well  to  know  what  to  expect  of  them. 


40 

CHAPTER  VIII. 
VALVES  OFF  THEIR  SEATS. 

Now  suppose  we  start  or  try  to  start  our  en- 
gine for  the  first  time,  and  on  opening  the 
throttle  find  that  the  engine  will  not  move,  or 
will  move  as  well  one  way  as  the  other  and 
without  power  in  any  direction.  We  know  that 
steam  is  in  the  chest  by  the  heat  of  it,  and  if 
everything  was  all  right  the  engine  should  do 
its  work;  since  it  does  not,  there  is  plainly 
something  wrong  with  the  slide  valve,  and  in 
nine  cases  out  of  ten  it  is  off  its  seat.  If  it  was 
simply  wrongly  set,  the  piston  would  go  one 
way  but  not  the  other  ;  it  would  make  a  great 
plunge  forward  or  backward  and  stop  there, 
but  it  would  not  drive  the  crank  over  the  cen- 
ter. A  slide  valve  does  not  require  much  to  lift 
it  from  its  seat,  and  it  may  occur  at  any  time  ; 
a  scale  blown  in  from  the  steam  pipe  may  get 
under  one  end  and  lift  it  enough  to  float  the 
valve,  then  the  steam  will  blow  through  the 
exhaust.  When  this  is  observed — blowing 
through — the  remedy  to  be  adopted  is,  in  the 
small  engines,  to  rap  the  valve  stem  smartly 
with  a  billet  of  wood,  when,  if  the  connection 
is  in  fault,  it  will  frequently  release  the  valve 
and  allow  it  to  seat  itself.  If  something  has 


41 

got  under  the  edge  of  the  valve,  move  the  stem 
as  rapidly  as  possible  back  and  forth,  and  it 
will  work  the  obstruction  off.  If  all  these  fail 
the  only  remedy  is  to  open  the  chest  and  get 
at  the  valve  itself.  If  water  gets  into  the  cylin- 
der in  any  quantity  it  is  very  apt  to  jam  the 
valve  stem  connection  by  bearing  up  on  the 
under  side  of  the  valve  through  the  steam  port; 
it  may  even  bend  the  stem  in  small  engines. 
If  this  happens  do  not  undertake  any  hammer 
and  tongs  remedies,  but  disconnect  the  stem, 
heat  it  black  hot  and  straighten  it  with  a  mallet 
on  a  block  of  wood.  Cold  iron  or  steel  breaks 
easily. 

VALVE  STEM  GUIDES. 

In  most  modern  slide  valve  engines  the 
steam  chest  is  on  the  side — right  or  left  as  oc- 
casion demands  (usually  the  right),  and  the 
stem  is  directly  connected  to  the  eccentric  rod 
without  the  intervention  of  a  rock-shaft.  The 
end  of  the  stem  is  flattened,  or  squared,  and  is 
carried  in  a  guide  which  may  or  may  not  be  of 
service;  if  it  is  in  line  with  the  direct  travel  of 
the  valve  it  is,  but  experience  teaches  that 
these  apparently  harmless  guides  can  make  a 
great  deal  of  trouble  for  inexperienced  persons, 
who  fancy  that  the  stem  must  move  tightly  in 
them.  This  is  not  so;  the  outer  end  of  the 
valve  stem  must  not  be  tied  up  in  any  way, 


42 

but  must  be  at  perfect  liberty,  in  order  to  allow 
the  valve  to  lie  flat  on  its  seat.  '  The  only  use 
of  a  guide  on  a  valve  stem  is  to  prevent  the 
weight  of  the  eccentric  rod  from  springing  it 
downward,  and  to  carry  the  weight  of  the 
valve  stem  itself;  beyond  this  the  valve  re- 
quires no  guiding,  for  the  stem  will  attend  to 
that.  Do  not,  then,  screw  up  the  guide  on  the 
valve  stem  so  tightly  as  to  bind  it  in  any  way;  it 
should  work  freely  with  a  slight  play  in  all 
directions. 

GOVERNORS. 

Let  us  leave  the  valve  and  all  its  connec- 
tions, including  the  eccentric,  until  we  get 
further  in  our  investigations,  and  look  at  the 
governor  or  throttle  valve.  In  early  days  en- 
gine builders  made  their  own  governors;  these 
were  always  the  common  two-ball  governors 
which  regulated  the  engine  (or  pretended  to)  by 
means  of  a  butterfly  valve,  so-called,  in  the 
steam  pipe.  This  valve  was  merely  a  flat  piece 
of  brass  with  a  shaft  through  it,  hung  in  the 
steam  pipe  just  as  a  damper  is  hung-  in  a  stove 
pipe,  and  usually  one  of  these  devices  fitted 
about  as  well  as  the  other.  That  is  to  say,  the 
throttle  was  so  badly  fitted  that  it  did  not 
answer  its  purpose  at  all,  and,  added  to  this, 
its  position  in  the  steam  pipe  was  such  that  it 
defeated  its  own  object  The  valve  was  so  far 


43 

from  the  steam  chest  that  there  was  always  a 
supply  of  steam  between  it  and  the  main  slide 
valve  sufficient  to  run  the  engine  at  full  power; 
consequently,  when  the  load  on  the  engine 
was  reduced  and  the  engine  ran  faster,  the 
speed  was  not  checked  until  the  supply  ran 
out,  even  though  the  governor  had  partly 
closed  the  throttle;  then  when  the  supply  was 
worked  off  the  engine  slowed  down,  only  to 
repeat  the  irregular  motion  at  every  change  of 
load.  Moreover,  the  old-fashioned  two-ball 
governor  was  sluggish  in  its  motions.  The 
balls  had  to  move  through  considerable  arcs 
before  the  throttle  acted  at  all;  it  had  too  many 
joints,  which  bound  themselves  tight  by  their 
motion,  and  it  was  so  defective  that  it  was 
cast  aside  for  better  devices.  There  are  a 
good  many  descendants  of  the  same  family, 
however,  still  in  the  market,  and  they  have  the 
same  inherent  defects.  The  butterfly  valve  has 
wholly  disappeared;  at  the  present  time  no  one 
makes  them.  Neither  do  engine  builders 
make  their  own  governors.  Many  patented 
governors  for  steam  engines  are  manufactured 
by  parties  who  make  a  specialty  of  them,  and 
these  makers  use  a  simple  cylindrical  shell 
moving  in  n  cylinder  as  a  throttle  valve.  This 
works  easily  and  tightly,  and  is  a  vast  im- 
provement on  the  old  gear.  Its  faults  are 


44 

chiefly  those  of  adjustment,  and  arise  from 
neglect  or  carelessness  on  the  part  of  those 
who  run  the  engine.  The  parts  are  apt  to 
wear,  or  else  the  stem  gets  lengthened  by  un- 
screwing, so  that  the  valve  drops  from  its 
natural  osition  and  blinds  the  ports.  In 
caring  for  and  repairing  a  governor  all  that  is 
necessary  is  to  see  that  the  joints,  when  there 
are  any  (in  some  there  are  none,  as  in  the 
Pickering),  are  free,  the  pins  perfectly  round 
and  true,  and  free  from  burnt  oil  or  gum;  that 
the  stem  is  straight,  works  freely  and  has  no 
shoulders  on  it  from  working  in  one  place 
constantly,  and  that  the  valve  is  in  its  proper 
place  when  the  governor  is  geared  up. 

RUNNING  WITH  THE  SUN. 

There  are  a  great  many  persons  in  existence 
yet  who  put  faith  in  traditions,  and  who  will 
gravely  assure  one  that  such  or  such  a  ma- 
chine does  not  work  properly  because  it  does 
not  "run  with  the  sun."  This  is  a  notion 
that  is  firmly  believed  in  by  many  who  have 
faith,  but  no  reasoning  power.  The  sun  has 
no  influence  upon,  or  any  connection  with 
machines  made  by  man,  with  the  sole  excep- 
tion of  sun  dials,  and  any  machine  which  is  in 
order  will  just  run  as  well  "against  the  sun" 
as  "with  the  sun."  Therefore,  let  no  person 
impose  upon  you  by  telling  you  that  the  rea^ 


45 

son  a  bewitched  governor  does  not  work  is  be- 
cause it  runs  against  the  sun.  Suppose  the 
engine  stands  east  and  west,  how  can  it  run 
against  or  with  the  sun  ?  We  used  the  ex- 
pression "bewitched  governor"  in  a  figura- 
tive sense  only,  but  let  no  engineer  ever  give  up 
the  search  for  a  cause  of  bad  working  in  a  de- 
tail. It  may  be  hidden,  but  it  can  be  found 
by  searching.  There  is  always  a  cause  for  ir- 
regular action  in  all  machines. 


CHAPTER   IX. 
ECCENTRICS  AND  CONNECTIONS. 

The  office  performed  by  an  eccentric  is  to 
move  the  valve  to  admit  steam  at  alternate 
ends  of  the  cylinder.  The  eccentric  is  simply 
a  wheel  hung-  out  of  its  own  center.  Its  own 
center  is  a  point  equi-distant  from  the  circum- 
ference. If  hung  on  a  shaft  in  this  way  it 
would  have  no  other  motion  than  a  true  rotary 
or  concentric  motion  around  the  shaft,  the 
same  as  a  flywheel  has  on  its  shaft.  Being 
hung  out  of  its  center,  it  has  an  untrue  motion 
— an  eccentric  one — from  which  it  takes  its 
name.  This  explanation  may  sound  somewhat 
puerile  to  experts,  but  there  is  an  idea  in  the 
minds  of  many  that  an  eccentric  has  some 
mysterious  action  which  makes  it  especially 
fit  for  driving  steam  valves.  We  have  been 
told  by  some  that  the  eccentric  ran  fast  and 
slow  without  reference  to  the  speed  of  rotation 
of  the  engine,  and  it  had,  for  that  reason,  a 
"dwell,"  so  to  call  it,  at  each  end  of  the  stroke, 
that  permitted  the  steam  to  enter  quickly  and 
to  escape  freely.  The  ''dwell"  exists,  but  it 
is  is  not  by  reason  of  any  peculiarity  of  the 
eccentric  itself,  but  on  account  of  changing  the 
motion  of  the  valve  from  forward  to  back.  At 


47 

this  period  in  the  stroke  the  eccentric  and  all 
its  connections  are  in  line,  see  fig.  7,  and  for  a 
portion  of  the  stroke,  from  a  to  6,  the  eccentric 
exerts  little  or  no  effect  upon  its  rod  and  the 
connections  to  it ;  in  itself,  however,  it  is  mov- 
ing- at  the  same  speed  it  always  moves  at, 


Fig.  7. 


which  speed  is  that  of  the  engine.  The  idea 
that  an  eccentric  has  a  variable  speed  doubt- 
less arose  from  some  one  looking  at  the  long 
side  of  it  passing  over  the  shaft  rapidly,  and 
comparing  it  with  the  short  side,  which  does 
move  slower  than  the  long  side,  because  it  is 
nearer  the  center  of  the  shaft.  Now,  an  ec- 
centric is  hung  out  of  its  own  center  just  half 
the  stroke  of  the  valve,  because  in  a  complete 
revolution  it  will  double  this  throw,  as  it  is 
called.  The  throw  of  an  eccentric,  then,  is  the 
amount  it  is  out  of  truth  (fig.  7),  or  the  distance 


48 

from  the  center  of  the  shaft  to  the  center  of  the 
eccentric.  Suppose  this  to  be  i}^  inches, 
then  the  eccentric  is  said  to  have  i*4  inches 
throw,  and  the  travel  of  the  valve  is  three 
inches. 

Connections  from  the  valve  stem  to  the  ec- 
centric are  of  various  kinds.  Where  the  steam 
chest  is  on  the  side  the  eccentric  rod  is  con- 
nected directly  to  the  valve  stem  by  a  pin  on 
the  side  of  the  stem,  or  by  a  spade  handle,  as 
it  is  called,  worked  on  the  stem  itself.  Some- 
times, however,  as  when  the  steam  chest  is 
not  on  the  side,  there  is  a  rock  shaft  between 
the  eccentric  and  valve  stem.  This  makes  no 
difference  in  the  action  of  the  eccentric,  but 
makes  some  difference  in  the  position  of  it  on 
the  shaft,  as  will  appear  later  on  in  this  series. 
Sometimes  there  is  an  idler  shaft,  which  also 
rocks,  but  makes  no  difference  in  the  position 
of  the  eccentric  on  the  shaft  from  that  which  it 
occupies  when  directly  connected.  The  con- 
nections are  in  all  cases  merely  carriers  or  dis- 
tributers of  motion  between  the  eccentric  and 
the  valve  itself,  and  need  not  be  considered  as 
affecting  the  motion,  except  as  hereafter  ap- 
pears. 

THE  CRANK  PIN. 

There  is  no  more  important  adjunct  of  an 
engine  than  the  crank  pin,  for  through  it  all  the 


49 

power  of  the  steam  is  transmitted.  This  state- 
ment does  not  refer  to  its  office  wholly,  but  to 
its  condition  and  its  construction.  In  most 
cases  engineers  are  powerless  to  alter  this  with- 
out going-  to  a  great  deal  of  expense,  but  they 
can  at  all  times  keep  it  in  good  order,  and  in 
such  condition  that  the  friction  of  it  is  reduced 
as  much  as  possible.  Engineers  worthy  of  the 
name  take  the  greatest  pride  in  having  this  de- 
tail free  from  every  scratch  or  flaw  on  its 
working  face,  and,  above  all,  never  allow  it  to 
get  more  than  hand-warm  ;  that  is,  about  the 
heat  of  the  human  hand.  It  should  not  heat  at 
all  if  properly  attended  to  and  when  properly 
proportioned  in  the  first  instance,  but  there  are 
many  proprietors  who  run  engines  much  be- 
yond the  power  they  were  intended  for,  and 
when  this  is  the  case  the  crank  pin  is  liable  to 
suffer  first.  Crank  pins  heat  from  several 
causes.  When  they  have  always  run  cool 
with  the  normal  load  on  the  engine,  and  de- 
velop a  tendency  to  heat  when  the  load  is  in- 
creased, the  cause  is  too  much  pressure  per 
square  inch  of  surface  ;  this  forces  out  the  oil 
and  brings  the  boxes  into  forcible  contact  with 
the  pin,  so  that  heat  is  engendered.  A  remedy 
in  cases  like  this  is  to  use  a  heavy  oil,  or  a 
grease  composed  of  equal  parts  of  plumbago 
and  tallow  or  lard.  This  finds  its  way  into 
4 


50 

the  most  minute  ridges  or  imperfections  in  the 
bearing-,  and  keeps  the  surfaces  apart ;  it  is  a 
very  excellent  lubricant  to  use  upon  an  over- 
loaded   engine.       More    generally,    however, 
crank  pins  heat  from  constant  tinkering  with 
the  connecting  rod  end.     An  engineer  hears  a 
pound,  and  arguing  at  once  that  the  crank  pin 
brass  must  he  slack,  drives  the  key  down,  with 
the  result  of  heating  the  pin.     Now  this  matter 
of  adjusting  brasses  on  crank  pins  and  on  other 
bearings  is  an  important  one,  not  so  well  un- 
derstood as  it  should  be.     In   a  great   many 
cases  the  brasses  are  not  properly  fitted  when 
they  leave  the  shop,  and  are  liable  to  cause 
trouble  from  that  fact.     High  speed  engines  of 
the  best  class  are  properly  made,  for  the  build- 
ers of  them  are  men  of  experience,  but  there 
are  some  persons  who,   as  soon   as  they  get 
charge  of  such  engines,  proceed  to  "relieve" 
the  brasses  in  the  wrong  place,  so  that  they  can 
key  them  up.     Now  what  is  good  for  a  high 
speed  engine  is  good  for  a  slow  speed  engine, 
and  every  bearing,  no  matter  what  its   office, 
should  bear  "  brass  and  brass,"  as  the  term  is, 
and  shown  in  the  diagram  at  a — not  as  shown 
at  b.     The  brasses  should  butt  solidly  and  fairly 
together,  and  the  pin  should  work  easily  inside 
of  them.     Then  it  will  have  merely  the  friction 
of  work,  and  not  the  friction  due  to  the   work, 


51 

with  that  due  to  the  pressure  of  the  key  added. 
Many  persons  hold  that  no  more  pressure  can 
be  put  upon  a  crank  pin  than  that  due  to  the 
work,  and  unless  the  pressure  of  the  key  or 
bolts  exceeds  that  of  the  work,  it  adds  nothing 
to  the  labor  of  the  bearing.  Those  who  hold 
this  view  are  requested  to  try  the  experiment 
of  driving  in  the  key  a  little  on  a  bearing  which 
shows  signs  of  heating.  They  will  speedily 


Fig. 


relinquish  their  theory.  Another  cause  of  heat- 
ing of  crank  pins  and  other  bearings  is  faulty 
workmanship.  The  brasses  do  not  bear  fairly  or 
seat  squarely  and  while  they  appear  all  right  to 
the  eye  they  are  not  all  right  to  the  bearing, 
which  speedily  gets  warm  over  the  matter.  A 
crank  pin  brass  must  seat  squarely  on  the  end 
of  the  connecting  rod,  and  the  rod  end  itself 
must  be  square.  If  the  key,  when  driven, 


52 

forces  the  brass  to  one  side  or  the  other,  and 
twists  the  strap  on  the  rod  so  that  its  sharp 
edges  can  be  felt  on  the  side,  it  will  draw  the 
brass  a-cock-bill  on  the  pin,  and  make  it  bear 
the  hardest  on  one  side  of  it,  reducing  the  area 
for  working  by  the  amount  it  is  out  of  truth. 
The  same  condition  of  things  is  true  of  the 
main  bearing.  If  the  brasses  do  not  bed  fairly 
on  the  bottom  of  the  pillow  block  casting,  and 
do  not  go  down  evenly,  without  springing  in 
any  way,  they  will  not  run  as  they  should.  It 
matters  not  whether  an  engineer  is  a  workman 
or  not,  in  regard  to  his  seeing  these  things. 
When  they  are  pointed  out  to  him,  he  can,  and 
that  is  our  reason  for  directing  attention  to 
them.  If  he  knows  where  the  fault  is  he  can 
find  men  to  remedy  it. 

Another  cause  of  heating  in  bearings  is  too 
much  surface  in  contact  that  is  merely  friction- 
al.  This  is  best  explained  by  fig.  9,  where  all 
the  work  of  transferring  the  power  of  the  steam 
is  done  upon  the  surface  of  the  pin,  which  is 
shown  in  section.  All  the  bearing  beyond 
this  is  of  no  service,  but  is  a  positive  injury  if 
if  touches  the  pin,  for  it  merely  rubs  and  wears, 
without  doing  any  good.  Engineers  then 
"  clear  "  the  brass  on  its  sides  as  shown  in  fig. 
9,  for  all  bearings,  whether  those  of  the  main 
shaft  or  elsewhere.  We  say  "clear"  the  brass 


53 

which  means  that  it  is  to  be  just  free,  or  so  that 
it  does  not  touch;  not  as  shown  in  the  diagram, 
where  it  has  to  be  exaggerated  to  be  seen  at 
all.  This  clearance  has  another  value,  that  of 
permitting  the  oil  to  stay  on  the  pin,  and  to 
cover  it  at  all  times.  This  end  is  also  furthered 
by  cutting  X  grooves  in  the  brasses,  but  this 
practice  we  have  never  been  greatly  in  favor 
of,  except  in  solid  brasses  which  oscillate,  or 


Fig.  9. 

do  not  completely  traverse  the  pin.  For  these 
last  oil  grooves  are  essential,  inasmuch  as 
when  they  are  hard  worked  the  oil  is  not  dis- 
tributed as  it  is  in  a  complete  revolution,  and 
they  are  very  liable  to  cut  from  want  of  access 
of  the  oil  to  all  parts.  Oil  grooves,  however, 
have  the  disadvantage  of  retaining  dirt  which 
may  find  its  way  in,  they  invite  fracture,  and 
they  reduce  the  bearing  surface.  They  are  not 
to  be  used  indiscriminately. 
No  greater  annoyance  can  happen  to  an  en- 


54 

gineerthan  to  have  bearings  heat  beyond  a  cer- 
tain degree.  When  shafts  run  hand  warm  it  is 
no  great  matter,  but  it  is  better  to  have  them 
quite  cold,  for  then  they  do  not  give  any  anxi- 
ety lest  they  should  become  hot.  Heat  of  any 
degree  about  a  bearing  is  certain  evidence  of 
friction;  what  causes  it  is  for  an  engineer  to  find 
out.  If  all  bearings  about  an  engine  were  ab- 
solutely parallel  to  each  other,  perfectly  round, 
smooth,  and  true,  of  ample  area  and  properly 
lubricated,  they  certainly  would  not  give  any 
trouble,  but  it  is  because  some  of  the  qualities 
above  mentioned  are  lacking  that  they  do  give 
trouble.  Want  of  proper  materials  in  contact 
is  also  a  cause  of  heating;  dirty  lubricating  oil, 
or  that  which  is  too  light  in  body  for  the  work 
to  be  done,  will  also  work  badly  for  an  en- 
gineer. Badly  designed  engine  frames  cause 
heating  of  main  bearings  by  springing;  settling- 
of  foundations,  and  badly  fitted  bearings  do  the 
same.  For  example,  if  on  taking  up  a  bearing 
that  heats,  the  brass  is  found  to  bear  as  shown 
by  the  shaded  lines  in  figure  10,  the  remedy 
is  to  scrape  away  the  shaded  portions  so  as  to 
have  a  fair  bearing,  but  before  doing  this  an 
engineer  should  be  sure  that  the  fault  is  in  the 
brass  and  not  in  some  part  of  the  pillow  block, 
or  other  detail  that  holds  the  brass  in  its  place. 
Brasses  are  usually  made  as  light  as  possible  to 


55 

save  material,  and  it  is  a  very  easy  matter  to 
spring  them  in  fitting  up.  If  they  are  so  sprung 
it  is  of  no  use  to  refit  the  bearing  itself,  because 
that  does  not  cure  the  trouble.  It  will  continue 
to  bear  badly  until  worn  out  if  the  cause  which 
springs  it  is  in  existence.  Get  the  spring  out 
first,  and  then  refit  the  bearing,  and  there  will 
be  no  trouble.  Chronic  heating  in  brasses  is 
almost  always  caused  by  this  defect — badly 


fitting  brasses.  Another  cause  is,  as  stated, 
dirt,  pure  and  simple.  This  need  not  be  like 
sand  or  gravel  to  give  trouble.  Sometimes 
dirt  gets  in  with  the  oil.  All  oil  should  be 
strained  through  a  cloth,  no  matter  how  clear 
it  looks.  There  is  a  great  deal  of  dirt  in  lubri- 
cating oil  ot  the  average  quality,  as  engineers 
find  who  strain  it.  Dirt  also  gets  in  through 


56 

carelessness.  Any  work  done  on  a  floor  over  an 
engine  shakes  dirt  down  upon  it  at  some  time 
or  other,  and  all  floors  over  engines  should  be 
ceiled  absolutely  dust  proof  by  laying  paper 
between  the  planks.  Imperfect  lubrication  is 
also  a  source  of  difficulty  with  bearings, 
though,  as  a  rule,  there  is  oftener  too  much  oil 
used  than  too  little. 


57 


CHAPTER   X. 

ADJUSTMENT  OF  BEARINGS. 

Another,  and  perhaps  a  by  far  too  common 
cause  of  trouble  with  bearings,  is  improper  ad- 
justment of  them;  that  is  to  say,  to  the  friction 
of  the  load  proper  is  added  the  friction  caused 
by  excessive  tightening*  of  the  bolts  and  nuts, 
or  gibs  and  keys.  It  is  easy  to  see,  we  think, 
that  the  office  of  a  bearing  is  simply  to  hold  the 
detail  in  its  place  while  it  is  at  work.  A  gib 
and  key  will  not  only  do  this,  but  it  will  also 
permit  an  engineer  to  take  up  a  bearing  as  it 
wears,  in  other  words,  make  it  larger  or  smaller. 
Now,  this  is  not  a  virtue,  by  any  means,  but  a 
defect,  for  it  gives  an  opportunity  for  careless 
men  to  do  mischief  through  want  of  judgment. 
Men  who  do  not  think,  so  soon  as  they  hear  a 
pound  or  a  noise  about  an  engine,  immediately 
accuse  some  bearing  and  go  at  it  with  a  ham- 
mer or  a  wrench,  and  tighten  it  up.  Bearings 
on  an  engine  which  is  in  line  and  in  good  or- 
der seldom  require  any  attention  of  this  kind. 
It  is  really  surprising  how  long  they  will  run 
without  being  touched  in  any  way.  We  know 
of  stationary  engines  doing  heavy  duty  which 
have  not  had  the  crank-pin  bearing  touched  in 
three  years,  and  from  which  not  a  sound 


comes.  It  is  the  same  with  the  main  bearings; 
where  everything  is  in  good  order  they  do  not 
want  any  tinkering,  and  the  best  evidence  an 
engine  can  give  that  it  is  not  in  order  is  noisy 
action.  We  know  of  some  stationary  engines 
that  run  at  high  speeds  (240  revs,  per  minute 
constantly),  yet  no  one  would  know  they  were 
running  if. they  turned  their  back  upon  them. 
They  are  actually  and  absolutely  noiseless. 
Not  one  penny  has  been  spent  upon  them  for 
repairs  in  over  two  years,  and  no  tinkering  of 
any  kind  has  been  done  upon  them.  Facts 
like  these  prove  our  assertion  that  perfectly  ad- 
justed bearings  and  good  workmanship  com- 
bined will  run  satisfactorily  for  long  periods. 
Unfortunately,  not  every  engine  is  the  best  of 
its  kind,  and  engineers  can  not  always  control 
the  conditions.  In  other  words  they  can  not 
rebuild  the  engines,  and  we  are  willing  to  ad- 
mit that  there  are  some  engines  which  it  is 
very  hard  to  "get  the  pound  out  of."  Let  it  be 
borne  in  mind  just  what  the  office  of  a  bearing 
is,  however,  and  much  can  be  done  to  lessen 
the  annoyance  of  pounding.  Reference  will  be 
made  to  this  further  on  in  this  work,  as  some 
of  it  is  due  to  faulty  valve  setting. 

THE  VALVE  AND  GEARING. 
Having  now   gone   from   the   cylinder  head 
to  the  main  shaft  of  our  engine,  and  briefly  re- 


59 

viewed  the  principal  details,  let  us  go  back  to 
the  steam  chest  again  and  look  at  the  slide 
valve  and  the  valve  seat,  as  shown  in  fig  i. 
Let  us  compare  them  and  see  what  relation 
they  bear  to  one  another.  The  office  of  the 
valve  is  to  open  and  close  the  ports  alternately, 
as  we  all  know,  and  if  it  is  rightly  made,  it  will 
do  this  unfailingly,  but  it  too  often  happens 
that  it  is  not  rightly  made,  but  is  simply  a  cast- 
iron  box  stuck  in  the  steam  chest  anyhow,  as 
we  may  say.  Sometimes,  in  small  shops  (and 
in  large  ones  for  that  matter),  foremen  get 
notions  in  their  heads  that  a  slide  valve  was 
never  made  until  they  got  one  up,  and  the  man 
who  is  afflicted  with  an  engine  of  this  kind  has 
a  big  bill  for  fuel.  At  other  times  engineers 
themselves  get  notions  as  to  exhaust  lap  and 
exhaust  lead,  and  cut  away  or  add  to  slide 
valves  that  were  in  perfect  order  before  they 
meddled  with  them.  We  have  no  theories  of 
any  kind  to  propound,  and  no  hobbies  to  ride, 
and  shall  illustrate,  therefore,  only  the  usual 
defects  and  the  methods  of  curing  them,  leav- 
ing every  one  to  adopt  or  reject  them  as  they 
see  fit. 

Figs,  n,  12,  13,  show  the  slide  valve  in 
various  positions:  the  first  one  at  mid-stroke, 
where  it  covers  both  ports;  the  second  with 
lead,  or  just  opening  the  port;  and  the  third 


6o 

with  the  port  full  open.  This  valve  is  shown 
as  having  line  and  line  exhaust,  that  is  to  say, 
without  lap  on  the  exhaust  side.  The  result  is 
shown  by  looking  at  a,  fig.  12,  where  the  steam 
is  passing  out,  as  shown  by  the  arrow;  it  has  a 
free  exit,  to  the  extent  of  half  the  steam  port 


nearly,  when  the  crank  is  nearly  on  the  center, 
but  the  exhaust  began  to  open  before  the  piston 
arrived  at  the  end  of  its  stroke.  This  is  just 
the  point  where,  it  is  claimed  by  those  who  are 


p 

1 

1 

1 

1 

1 

'//^y////^ 

\  

§ 

v  

1 

H 

62 

in  favor  of  inside  lap  on  a  slide  valve,  that  an 
error  is  made,  because  it  lets  the  steam  escape 
before  it  has  done  all  the  work  that  it  can.  In 
some  measure  this  is  true,  because  every  inch 
that  a  piston  travels  under  pressure  gives 
power,  but  the  diagram,  fig.  14,  shows,  to  our 
mind,  that  the  steam  on  the  last  quarter  of  the 
piston  stroke  does  very  little  work  indeed.  It 
is  at  a  comparatively  low  pressure,  having 
been  expanded  through  the  cylinder,  and  the 
force  exerted  by  it  is  spent  upon  a  crank  whose 
radius  is  shown  at  a,  fig.  14,  and  not  in  a  direct 
line,  or  at  right  angles  with  the  line  of  motion, 
but  at  a  very  obtuse  angle,  as  shown  by  the 
dotted  lines,  so  that  the  effort  to  turn  the  crank 
is  absorbed  to  a  great  extent  before  it  reaches 
the  shaft  itself.  Suppose  we  do  add  inside  lap, 
as  shown  by  the  dotted  lines  at  b,  figs.  12,  13, 
to  the  extent  of  half  the  steam  lap,  then  we  re- 
tain the  steam  in  the  cylinder  until  the  piston 
has  completed  its  stroke;  we  follow  it  up 
with  spent  steam  until  it  begins  the  re- 
turn stroke;  we  get  a  full  exhaust  of 
the  spent  steam  through  the  steam  port,  but 
we  lose  nearly  half  the  area  of  the  exhaust  port 
in  the  valve  seat,  so  that,  as  shown  at<r,  fig.  13, 
which  ever  plan  we  adopt,  whether  line  and 
line  exhaust,  or  lap  on  the  exhaust  side  of  the 
valve,  we  have  to  sacrifice  something,  and  the 


63 

general  sentiment  of  experienced  engineers  is 
in  favor  of  a  line  and  line  exhaust.  The  first 
thing  an  old  engineer  does  who  finds  a  valve 
with  inside  lap  on  it,  is  to  chip  the  lap  off,  and 
swear  some  at  the  man  who  put  it  on. 

In  saying  this,  however,  we  must  qualify  it 
to  this  extent:  that  there  may  be  cases  where 
line  and  line  exhaust  is  inadmissible  or  unde- 
sirable by  reason  of  the  proportions  of  valve 
face  and  steam  ports.  Our  diagram  shows  the 
usual  proportion  of  good  practice.  This  is, 
that  the  bridge  or  metal  between  the  two  ports 
(steam  and  exhaust)  is  equal  to  the  width  of 
the  steam  port,  and  the  exhaust  is  twice  the 
width  of  the  steam  port.  Not  all  valve  faces 
and  steam  ports  are  so  made,  and  the  change 
involves  some  changes  in  valve  construction 
and  operation  of  the  engine;  but  it  is  manifest 
that  we  can  not  treat  upon  this  exhaustively  in 
this  work.  The  best  arrangement  for  the  ex- 
haust must  be  determined  for  each  engine  by 
an  indicator,  which  is  the  only  friend  an  en- 
gineer has  to  tell  him  what  is  going  on  where 
he  can  not  see  directly. 

These  examples,  it  is  understood,  all  exhibit 
the  action  of  a  slide  valve  when  working  at  full 
stroke,  or  without  cut-off,  and  from  them  it  is 
easy  to  see  that  the  evils  of  choking  the  ex- 
haust and  wiredrawing  the  live  steam  (that  is, 


64 

admitting  it  through  a  very  narrow  opening  in 
the  valve  face),  are  increased  when  steam  is 
used  expansively,  hence  the  unfitness  of  a  slide 
valve  for  an  automatic  cut-off  is  readily  under- 
stood. It  is  especially  seen  in  locomotives, 


where,  with  a  short  cut-off,  used  at  high  speeds, 
the  exhaust  is  actually  punched  out  by  the  pis- 
ton, for  it  begins  to  be  compressed  at  half 
stroke,  as  shown  by  this  card,  fig.  15,  which 
was  taken  from  a  locomotive  on  a  fast  run. 


CHAPTER   XL- 
SETTING  ECCENTRICS. 

This  detail  is  one  of  the  simplest  duties  an 
engineer  has  to  perform,  but  it  is  sometimes 
made  a  very  mysterious  matter.  Elaborate 
preparations  are  made  ;  much  peering  into  the 
steam  chest  takes  place,  and  the  chief  perform- 
er looks  very  wise.  There  is  no  occasion  for 
performances  of  this  character,  for  the  whole 
operation  from  first  to  last  should  not  consume 
ten  minutes,  and  a  man  of  experience  can  set 
an  eccentric  at  the  first  turn  over,  generally, 
after  the  valve  is  squared.  This  last  means 
that  the  valve  shall  open  both  ports  alike. 
Squaring  the  valve  also  makes  the  eccentric  rod 
of  the  proper  length,  and  until  the  valve  is 
squared  no  setting  of  the  eccentric  can  be  done. 
Take  notice  that  it  is  the  eccentric  which  is  to 
be  set,  not  the  valve.  The  valve  occupies 
various  positions  on  the  valve  seat,  but  the  ec- 
centric has  a  fixed  position  on  the  shaft  for 
each  particular  valve.  In  one  work  on  the 
slide  valve  the  operation  of  setting  an  eccen- 
tric occupies  two  pages  of  directions,  and  end- 
less a  6's,  c  d's,  xys,  and  other  letters  of  refer- 
ence which  arc  wholly  useless.  We  never 
found  any  italics  on  valve  stems,  or  on  eccen- 
trics ourselves.  Moreover,  much  time  is  spent 
5 


with  trams,  etc.,  in  getting  the  exact  mathe- 
matical center,  or  putting  the  crank  pin  exact- 
ly midway  in  its  orbit,  all  of  which  is  useless 
work.  An  eccentric  can  be  set  without  any 
heavy  flywheel  to  turn,  or  connections  to  drag 
hither  and  yon.  Every  part  of  the  working 
gear  not  actually  connected  with  the  eccentric 
and  valve  should  be  taken  off,  for  it  only  cre- 
ates friction  for  nothing. 

THE  ACTUAL  OPERATION. 

Take  out  the  crank  pin  (unless  it  is  riveted 
in)  and  run  a  line  through  the  cylinder. 

Put  on  the  eccentric  strap  and  connect  it  to 
the  valve  stem,  just  as  if  it  was  under  steam. 

Now  turn  the  crank  shaft  the  way  the  engine 
is  to  run  by  any  means  that  will  turn  it.  If 
the  flywheel  is  on  use  that  for  a  lever. 

Look  in  the  steam  chest  and  see  if  the  valve 
opens  both  ports  equally. 

If  it  does  not,  shorten  or  lengthen  the  stem 
half  the  difference,  until  the  eccentric  moves 
the  valve  properly. 

Now  put  the  crank  on  its  center  by  the  line, 
and  move  the  eccentric  around  on  the  shaft 
until  it  opens  the  port  slightly,  and  stands  as 
shown  in  the  diagram,  figure  16,  at  i. 

Turn  crank  I  on  the  other  center,  and  the 
valve  will  show  more  or  less  off  of  the  position 
it  had  when  on  the  other  center.  Divide  the 


6; 

difference  by    lengthening   or    shortening    the 
valve  stem  half  the  amount  of  error  (for  what 


v- 


is  taken  off  one  end  is  put  on  the  other  in  one 
revolution),  and  the  work  is  done. 


68 

There  is  no  occasion  to  have  the  connecting1 
rod  or  the  piston  in  ;  they  have  nothing  what- 
ever to  do  with  setting  the  eccentric.  This 
should  be  done  the  first  thing  after  the  shaft  is 
in  place,  not  when  the  details  are  all  in.  Once 
set,  the  eccentric  is  always  set,  unless  it  is 
shifted  by  chance.  When  it  is  once  in  place, 
it  should  be  marked  with  a  chisel,  so  that  it  can 
be  put  back  if  accidentally  slipped 

There  are  a  good  many  who  will  object  to 
this  method  of  setting  an  eccentric,  because  it 
is  out  of  the  usual  way;  but  it  is  as  exact  in  re- 
sult as  any  other  way.  There  is  no  use  in 
fussing  with  trams  to  get  the  exact  mathemati- 
cal center  of  the  flywheel,  because  (unless  the 
valve  has  no  lap)  no  engine  takes  steam  on  the 
exact  center.  It  always  has  more  or  less  lead, 
the  amount  of  which  must  be  finally  adjusted 
by  an  indicator  for  the  work  to  be  perfect.  It 
will  be  seen  by  figure  16  that  the  eccentric  is 
slightly  in  advance  of  the  crank;  that  is  to  say, 
that  its  center  line  is  not  the  crank's  center 
line.  The  angle  so  formed  is  called  the  angle 
of  advance,  and  the  advance  is  made  to  take 
up  the  lap  and  to  give  lead,  as  shown  in  fig.  16. 
We  must  here  say  that  in  all  cases  the  valve 
will  be  "late,"  as  it  is  called,  on  the  back  end 
steam  port,  and  this  port  will  not  open  so  fully 
as  the  front  end  port.  As  the  explanation  of 


69 

this  involves  a  diagram,  which,  owing  to  the 
limits  of  the  page  in  the  work,  would  be  very  in- 
tricate, and  not  at  all  clear  to  inexperienced 
persons,  we  shall  not  attempt  one,  but  say  that 
the  error  is  due  to  the  fact  that  a  fixed  point  on 
the  eccentric  rod  in  one  revolution,  and  a  fixed 
point  on  the  connecting  rod  in  one  revolution, 
forms  cycloids  of  diverse  areas  and  outlines, 
and  a  fixed  point  in  one  is  not  and  never  will 
be  coincident  with  a  fixed  point  in  the  other  ; 
the  eccentric  rod  is  always  behind,  varying  in 
degree  with  the  length  of  the  connecting  rod. 
If  the  latter  was  of  infinite  length,  there  would 
be  no  difference  in  the  action  of  a  slide  valve 
on  both  ends  of  the  cylinder,  but  the  shorter 
the  connecting  rod  is  the  greater  its  angle  of 
divergence  with  the  path  of  the  eccentric  rod, 
and  the  greater  the  error  in  the  valve  motion. 

Suppose  we  could  drive  a  nail  through  the 
side  of  a  connecting  rod,  and  could  hold  a 
board  up  to  it  while  the  engine  was  running: 
then  the  figure  described  would  be  a  cycloid,  or 
egg-shaped.  Now  drive  a  nail  through  the  ec- 
centric rod,  and  the  figure  described  by  it 
would  be  a  cycloid  also,  but  different  in  out- 
line and  area,  and  the  shorter  the  connecting 
rod  the  greater  would  be  the  discrepancies. 
This  is,  in  brief,  the  cause  of  the  difference  in 
port  opening  for  both  ends  of  the  cylinder,  but 


yo 

it  affects  the  action  not  at  all.  There  are  many 
valve  motions  which  seek  to  overcome  this  so- 
called  evil,  and  such  motions  are  called  radial 
valve  gears,  for  they  operate  the  valve  by  levers 
instead  of  eccentrics  ;  some  of  them  have  ec- 
centrics also  ;  one  only  for  both  motions,  for- 
ward and  back.  These  are  used  chiefly  on  lo- 
comotives and  screw  propellers,  and  the  cy- 
cloid described  by  the  valve  stem  connection 
is  a  very  close  approximation  to  that  of  the 
connecting  rod,  so  that  the  port  openings  are 
practically  equal,  and  the  cut-off  is  equal  for 
all  points  of  the  stroke.  This  makes  a  better 
distribution  of  steam,  and  raises  the  efficiency 
of  the  whole  machine  to  some  extent ;  but  the 
actual  values  of  these  gears  is  very  slight  when 
compared  to  the  cost  of  keeping-  them  up,  and 
their  inaccessibility  when  in  motion.  The  ob- 
ject of  putting  lead  on  a  valve  is  to  fill  the 
ports  with  live  steam,  for  one  thing,  and  to 
check  the  motion  of  the  piston  gradually  so 
that  it  will  cushion  on  live  steam.  The  amount 
of  lead  varies  with  the  character  of  the  work. 
Engines  which  run  slow,  say  50  to  60  revs,  per 
minute,  require  very  little,  but  high  speed  en- 
gines should  have  more.  Say  that  our  piston 
.is  12"  diameter  and  the  engine  makes  60  revs. 
per  minute;  then  i-32d  of  an  inch  is  ample  lead 
for  the  valve.  A  great  deal  of  steam  can  get 


through  an  opening  of  this  dimension,  but  if 
the  same  engine  makes  400  revs,  per  minute, 
then  the  valve  should  have  3-3  2 ds  lead,  and  may 
even  require  more.  Now,  the  link  motion,  as 
most  persons  know,  increases  the  lead  on  the 
valve  as  the  steam  is  cut  off.  It  is  useful  to 
bear  this  in  mind,  but  we  shall  not  attempt  an 
explanation  of  the  cause. 

This  work,  as  its  title  indicates,  gives  ele- 
mentary instruction  upon  the  operation  of  en- 
gines and  boilers,  and  we  do  not  mean  to  go 
outside  of  that  and  make  it  a  medley  of  several, 
different  branches  of  an  engineer's  profession. 
Moreover,  if  we  attempted  this  line  of  instruc- 
tion, we  should  only  repeat  the  researches  of 
others.  Those  who  want  a  treatise  upon  the 
link  motion  and  its  operation  should  purchase 
"Link  and  Valve  Motions"  by  Auchincloss,  which 
is  a  standard  work,  explained  in  the  clearest 
manner,  and  fully  illustrated. 

Setting  the  eccentrics  of  a  link  motion  is 
precisely  the  same  operation  as  that  of  any 
other,  with  this  difference  only  :  that  both 
rods,  back  and  go-ahead,  must  be  adjusted  for 
length  before  the  eccentrics  are  set,  for  a 
change  in  one  affects  the  action  of  the  other. 
Suppose,  for  example,  that  we  undertake  to  set 
the  go-ahead  side  before  the  backing  side  is 
corrected  for  length.  We  get  the  go-ahead 


73 

wheel  on  all  right,  but  when  we  throw  the 
backing  side  in  gear  and  set  it,  then  we  find, 
on  trying-  the  go-ahead  side,  that  it  is  out. 
This  is  caused  by  the  backing  eccentric  rod 
being  of  the  wrong  length.  Now,  if  we  have 
squared  the  valve  for  both  motions,  we  set  the 
eccentrics  as  shown  in  this  diagram,  fig.  17. 
This  position  answers  only  where  the  link  is 
directly  attached  to  the  valve  stem.  Where  a 
rock  shaft  is  used  the  dotted  lines  show  the  po- 
sition of  the  eccentrics. 

Setting  the  cut-off  valves  of  an  engine  is  a 
very  short  job.  Usually  these  valves  are  so 
fitted  that  they  operate  from  no  admission  at 
all — zero,  so  called — to  full  stroke.  Sometimes, 
however,  they  are  not  connected  to  the 
governor,  but  are  set  to  cut  off  at  some  fixed 
point,  say  one-half  of  the  stroke.  To  do  this, 
or  to  cut  off  at  any  point  of  the  stroke,  it  is 
only  necessary  to  square  the  valves  in  their 
travel  over  the  main  valve,  run  the  crosshead 
to  the  point  at  which  it  is  desired  to  cut  off  the 
steam,  set  the  valves  so  that  they  just  close  the 
main  steam  valve  port,  and  then  turn  the  eccen- 
tric around  on  the  shaft  until  it  will  connect 
with  the  cut-off  valve  gear.  Or,  connect  the 
cut-off  valve  gear  with  the  eccentric  and  then 
turn  the  same  on  the  shaft  until  it  just  closes 
the  ports  at  the  desired  point. 


74 


CHAPTER   XII. 
RETURN  CRANK  MOTION. 

The  return  crank  motion  is  the  same  as  an 
eccentric,  and  is  set  in  the  same  way.  It  has, 
however,  the  disadvantage  that  the  lead  can 
not  be  changed  unless  there  is  a  slot  for  the  pin 
a  to  move  in,  for,  as  will  be  seen  in  fig.  18, 
moving  the  return  crank  in  or  out  from  the 
center  of  the  main  shaft  merely  increases  the 
travel  of  the  valve,  the  lead  being  very  slightly 
affected. 

It  must  be  borne  in  mind  that  setting  the  ec- 
centrics of  an  engine  is  at  best  a  haphazard 
operation  when  it  is  done  while  the  engine  is 
cold.  Many  changes  lake  place  in  the  valves 
and  valve  motion  when  the  engine  has  been 
run  a  while  and  after  it  has  been  heated 
up.  Cast-iron  expands  materially  by  heat,  and 
the  valve  gearing  itself  stretches,  if  we. may  so 
term  it.  That  is  to  say,  the  strain  imposed 
upon  the  several  joints  and  connections  make 
the  actual  relation  of  the  valve  and  eccentric 
different  from  what  it  appeared  to  the  naked 
eye  when  the  steam  chest  was  open  and  the 
engine  was  cold. 

This  is  one  reason  why  it  is  unnecessary  to 
waste  time  in  finding  "absolute  centers"  of  en- 


75 

gines  with  a  tram.  All  have  to  be  corrected 
by  the  indicator  at  last,  for  that  is  the  only  in- 
strument we  have  for  detecting  the  actual  se- 
quences of  the  valve  and  valve  gearing  gener- 
ally. We  venture  to  say  that  a  good  steam 
distribution,  as  shown  by  the  evidence  of  a 
card,  will  bear  very  little  relation  to  the  ab- 
solute centers,  or  point  of  no  motion  of  the 
crank  and  piston. 


So  far  as  setting  eccentrics  is  concerned, 
many  of  them,  in  radial  valve  gears  particu- 
larly, are  forged  solid  on  the  shaft.  They  are  set 
in  the  drawing  room,  and  the  relative  lengths 
of  the  several  rods  are  plotted  out  on  the  draw- 
ing board.  It  must  be  borne  in  mind  also  that 
this  method  of  setting  an  eccentric,  as  to  its 
relative  position  with  the  crank  pin,  refers  only 
to  the  valves  which  slide  on  their  seats,  piston 
valves  included;  not  to  puppet  valves,  or  to  all 
forms  of  radial  gears.  The  great  majority, 
however,  stand  as  shown  in  the  preceding  dia- 


76 

grams.  The  influence  the  valve  has  on  the 
action  of  an  engine  is  very  great.  As  we  have 
said  in  previous  lines,  the  principal  object  of  it 
is  to  distribute  the  steam  properly  in  the  cyl- 
inder at  each  stroke,  and  incidentally,  to  cor- 
rect or  check  the  motion  of  the  several  parts 
at  the  end  of  the  stroke.  This  is  done  by  cush- 
ioning the  piston  on  a  bed  of  live  or  dead 
steam,  as  the  fancy,  or  the  teaching,  or  the  ex- 
perience, of  the  engineer  directs.  If  all  steam 
engines  were  perfectly  built  this  would  not  be 
necessary,  but  there  are  many  defects  of  con- 
struction and  erection  which  have  to  be  com- 
pensated for,  and  this  is  generally  done  by 
compressing  the  dead  steam,  or  admitting  live 
steam  in  the  form  of  lead.  The  crank  itself  is 
one  of  the  most  perfect  details  ever  devised  by 
man  for  gradually  absorbing  or  taking  up  the 
momentum  of  the  parts,  and  many  first-class 
engines  are  at  work  turning  their  centers  with 
neither  lead  nor  compression,  and  are  also 
noiseless  in  action,  but  this  can  not  be  done 
with  the  average  engine,  or  with  very  high 
speed  engines,  so  lead  and  cushioning,  or  com- 
pression, is  resorted  to. 

POUNDING. 

One  of  the  commonest  defects  of  steam  en- 
gines, and  one  that  is  the  most  annoying  to 
hear,  is  pounding,  so  called.  That  is  to  say 


77 

that  in  passing  the  centers  a  noise  is  heard, 
which  may  proceed  from  several  causes,  and 
is  distinctive  in  character  for  each  one.  These 
can  not  be  described  so  that  an  inexperienced 
person  can  tell  the  cause  of  it  from  the  noise. 
Detecting  or  locating  natural  noises,  so  to  call 
them,  or  the  sound  caused  by  the  natural  work- 
ing of  an  engine,  and  separating  them  from 
noise  caused  by  defective  action,  is  a  part  of 
an  engineer's  duties  which  can  only  be  gained 
by  experience;  so  we  shall  not  attempt  it,  but 
proceed  to  point  out  some  which  are  common. 
The  first  we  shall  mention  is  when  an  engine 
is  out  of  line. 

Take  a  chalk  line  and  stretch  it  taut,  so  that 
it  is  absolutely  straight,  without  sag.  This  rep- 
resents the  center  line  of  an  engine.  Now,  if 
every  detail  is  exactly  in  harmony  with  this, 
there  can  not  be  any  sound  from  an  engine.  If 
the  main  shaft  is  exactly  (mind  what  exactly 
means!)  at  right  angles  with  the  center  line, 
and  the  path  of  the  crank  is  exactly  true  also, 
if  the  crank  pin  is  absolutely  square  with  the 
center  line  of  the  shaft  and  revolves  mathemat- 
ically exact  with  it,  then  the  engine  is  in  line, 
and  the  fault  is  not  there. 

THE  CONNECTIONS. 

Now  look  at  the  connections.  Suppose  the 
connecting  rod  is  not  properly  fitted  up  or 


79 

keyed  up,  and  stands  off  from  the  crank  pin 
when  cast  loose  from  it,  as  shown  in  the  dia- 
gram, then  a  noise  will  be  heard  which  is 
caused  by  the  "chugging"  of  the  crosshead 
against  the  inside  of  the  guides  at  each  stroke; 
the  crank  pin  springing  the  crosshead  from  side 
to  side  at  each  revolution.  This  noise  is  hard 
to  locate  when  the  engine  is  at  work,  particu- 
larly if  the  guides  stand  vertically  and  are 
V-shaped,  as  in  Corliss  engines.  If  it  is  sus- 
pected as  a  cause  of  pounding,  disconnect  the 
crank  pin  end  of  the  connecting  rod  and  key 
up  the  crosshead  end  tightly;  then  the  rod  will 
show  for  itself  whether  it  hangs  square  or  not 
If  it  does  not  point  fair  for  the  exact  center  of 
the  crank  pin,  between  the  collars,  ease  off  on 
the  back  of  the  crosshead  brass  slightly,  so  as  to 
throw  the  rod  in  the  center  of  the  collars.  Try 
the  crank  on  both  centers,  and  if  the  rod  shows 
off  on  each  side,  right  and  left  alternately,  then 
the  main  shaft  is  out  of  line  and  must  be  brought 
true.  Where  there  is  a  heavy  belt  dragging  on 
the  outboard  end  of  a  main  shaft  it  is  very  apt 
-  to  haul  it  around  materially,  even  canting  the 
whole  outboard  foundation  sometimes,  if  the 
latter  is  high  and  narrow,  as  it  usually  is. 

We  have  stated  before  that  it  is  seldom  that 
bearings  are  so  slack  as  to  cause  a  pound.  The 
noise  of  a  slack  bearing  is  a  "chuck,"  so  to 


8o 

call  it,  and  not  a  pound  proper,  and  it  is  of  no 
use  to  endeavor  to  silence  a  noisy  engine  by 
screwing  or  keying  up  ;  that  only  makes  a  bad 
matter  worse.  Very  often  pounding  is  caused 
by  improperly  set  valves,  and  sometimes  a  lit- 
tle more  lead  or  less  compression  will  cause  it 
to  work  better. 

This,  it  must  be  borne  in  mind,  is  only  a 
rough  and  ready  method  of  finding  whether 
the  crank  shaft  is  true  or  not.  The  proper  way 
to  do  this  is  to  take  the  engine  apart,  run  cen- 
ter lines  through  the  cylinder  and  the  guides,  and 
see  whether  they  are  in  line  with  each  other.  A 
plumb  line  should  be  dropped  over  the  exact 
center  of  the  crank  shaft,  in  the  crank  pit,  so 
that  the  vertical  line  barely  touches  the  cylin- 
der line.  The  crank  pin  should  then  be  tried  by 
this  line,  so  as  to  ascertain  whether  it  is  equal- 
ly distant  from  it  on  top  and  bottom  centers. 

Sometimes  it  will  be  seen,  where  the  engine 
has  run  a  long  time,  that  the  shaft  needs  to  be 
raised  at  the  crank  end  in  order  to  bring  it 
square.  This  is  shown  by  the  center  in  the 
shaft  itself,  by  putting  a  square  en  the  end  of 
the  shaft  and  allowing  the  blade  to  come  gent- 
ly down  to  the  horizontal  center  line  through 
the  cylinder.  These  directions  are  very  easily 
understood  by  persons  who  have  had  experi- 
ence, but  those  who  have  not,  need  to  exercise 


8i 

care  in  using  the  square,  for  if  the  end  of  the 
shaft  itself  is  not  true  the  indications  of  the 
square  are  of  no  value.  Do  not  undertake  to 
true  any  horizontal  shaft  by  a  spirit  level. 
Shafts  are  not  the  same  size  all  the  way  ;  that 
is  to  say,  they  are  not  true  themselves,  not- 
withstanding that  they  may  have  been  turned 
and  are  apparently  true. 

Another  and  very  common  source  of  pound- 
ing in  an  engine  is  changing  the  valve  motion, 
or  re-setting  it,  and  overhauling  the  engine  for 
repairs.  If  the  valve  time  is  changed  so  that 
it  takes  steam  at  a  different  point  from  where 
it  formerly  did,  earlier  or  later,  the  pressure 
comes  in  a  different  place  on  the  crank  pin  and 
shaft,  which  are  worn  to  the  old  valve  motion. 
The  engine  will  not  work  then  smoothly  until 
the  brasses  are  refitted.  All  bearings  upon  en- 
gines that  have  been  overhauled  are  liable  to 
this  trouble,  and  it  is  an  exceedingly  difficult 
one  to  detect.  The  best  way  to  avoid  it  is  to  re- 
bore  all  brasses  and  re-turn  all  bearings  that 
can  be  so  treated.  The  main  shaft  can  not  be, 
but  the  crank  pin  may  be  "skinned  over,"  as 
it  is  called,  to  its  great  improvement  These 
things  properly  belong  to  refitting  an  engine 
in  a  machine  shop,  but  as  it  is  part  of  an  en- 
gineer's duties  to  know  them,  we  have  said  a 
few  words  in  that  direction. 
6 


82 

A  few  lines  back  we  made  a  brief  reference 
to  lining  up  an  engine  in  order  to  avoid  pound- 
ing, but  perhaps  a  diagram  and  more  explicit 
directions  as  to  putting  all  parts  in  line  will  be 
acceptable.  An  engine  out  of  line  never  will 
work  as  it  should,  and  as  it  is  a  very  simple 
matter  to  have  it  square  we  shall  give  plain 
directions  how  to  make  it  so. 

The  diagram,  fig.  20,  shows  a  side  elevation 
of  a  Corliss  engine.  In  the  crank-pit  is  a 
square  frame  made  of  boards,  stiff  enough  to 
hold  a  line  firmly  without  jar  or  tremor.  This 
frame  is  not  necessary  if  there  are  timbers 
overhead  or  at  the  end  of  the  frame  to  fasten  a 
line  to ;  the  frame  is  only  put  in  the  diagram 
to  show  the  process.  The  piston,  crosshead 
and  connecting  rod  are  taken  off  and  out  of  the 
engine,  and  a  line,  a,  is  stretched  through  the 
cylinder.  One  end  of  it  is  fastened  to  the  cross, 
3,  shown  in  diagram  C.  This  cross  is  made 
of  wood  firmly  fastened  together  and  having  a 
hole  in  the  exact  center  of  it  about  %  of  an 
inch  in  diameter,  or  larger  than  the  line  which 
goes  through  it,  and  the  line  is  held  by  a  piece 
of  wire  run  through  a  loop  in  the  end  of  the 
line,  so  that  by  moving  the  wire  one  way  or 
the  other,  the  line  can  be  centered  in  the  cylin- 
der independent  of  the  cross.  This  cylinder 
line  must  be  as  fine  as  possible,  hard-twisted 


84 

and  very  strong,  so  that  it  can  be  stretched  very 
tight  and  have  no  sag  whatever.  Run  this  line 
through  the  cylinder,  draw  it  up  tightly,  and 
then  center  it  absolutely  in  the  cylinder,  by 
cutting  sticks  half  the  diameter  of  the  cylinder, 
moving  the  crank  end  of  the  line  until  it  is  ab- 
solutely centered  in  the  cylinder  at  both  ends 
of  it.  Pay  no  attention  to  where  the  crank  end 
of  the  line  is  ;  let  it  go  where  it  will  with  refer- 
ence to  the  shaft  itself.  Now  make  a  tem- 
plate, B,  which  just  fits  the  guides  accurately, 
and  draw  lines  through  it,  as  at  c  and  d.  Where 
these  lines  cross  each  other  is  the  exact  center 
of  the  guides,  and  we  want  to  know  if  they  are 
centered  with  the  bore  of  the  cylinder.  If  the 
guides  are  worn  much,  it  will  be  in  the  center 
of  them,  where  the  greatest  stress  comes,  and 
this  cannot  of  course  be  changed  except  at 
great  expense ;  but  it  often  happens  that  the 
cylinder  shifts,  and  this  can  be  remedied  by  a 
good  machinist.  We  cannot  give  directions 
what  should  be  done  in  such  a  case,  but  must 
leave  the  matter  to  be  dealt  with  by  every  one 
to  suit  emergencies.  The  guides  and  cylinders 
o  Corliss  engines  are  supposed  to  be  abso- 
lutely in  line  when  new,  and  the  method  here 
illustrated  is  the  one  used  to  find  out  whether 
they  are  or  not.  Now  suppose  that  we  have 
our  line  centered  exactly  in  the  cylinder,  the 


85 

next  thing  we  want  to  know  is  whether  the 
shaft  is  exactly  in  the  center  of  it.  There  are 
two  ways  to  do  this,  and  one  of  them  is 
troublesome  and  expensive — the  other  is  not. 
We  show  the  easiest  way.  This  is  to  drop  the 
plumb  line,  e,  at  the  exact  center  of  the  shaft, 
so  that  it  just  clears  the  cylinder  line,  using  a 
try  square  on  the  end  of  the  shaft  with  a  blade 
long  enough  to  reach  the  intersection  of  the 
two  lines,  so  as  to  verify  them  ;  try  the  square 
on  both  sides  of  the  line,  front  and  back,  and 
the  centre  of  the  shaft  will  be  accurately  lo- 
cated. If  the  front  end  is  low,  the  remedy  is 
to  raise  it,  of  course,  but  before  moving  the 
shaft  forward  or  back  by  the  quarter  brasses, 
the  crank  must  be  tried  on  the  four  quarters  of 
its  circle  of  revolution.  This  will  show  at 
once  where  the  shaft  stands  with  reference  to 
the  horizontal  line,  a,  and  the  vertical  line,  e. 
Turn  the  crank  over  until  it  comes  up  to  the 
cylinder  lines,  as  in  figs.  21  and  22.  If  the 
crank-pin  is  exactly  midway  of  the  collars  with 
the  line,  it  is  right  on  that  center.  Now  try  it 
on  the  other  center,  and  it  will  perhaps  stand 
off ;  if  it  does,  the  remedy  is  very  plain.  Now 
spring  the  cylinder  line  on  one  side  so  that  the 
pin  will  pass  it,  and  try  the  crank-pin  on  the 
vertical  line,  e  (fig.  22);  if  it  stands  in  toward 
the  cylinder  line,  the  center  of  the  shaft  is  low 


86 


and  must  be  raised.  Try  it  on  'the  bottom  half 
center  also,  and  rectify  it  according  to  what  the 
line  says.  This  method  of  lining"  up  an  engine 
will  cause  the  crank  to  revolve  in  a  truly  verti- 
cal plane,  at  exact  right  angles  with  the  bore 
of  the  cylinder.  It  makes  no  difference  what 


CYLINDER   LINE 


Fig.   21    &  22 


kind  of  an  engine  it  is,  the  method  is  the  same 
for  all,  and  any  man  of  ordinary  intelligence 
can  put  his  engine  in  exact  line  if  he  follows 
these  directions. 
This  is  not  to  say,  however,  that  all  pound- 


87 

ing  will  cease  so  soon  as  he  has  done  so.  We 
have  fully  adverted,  in  former  chapters,  to  the 
causes  of  this,  and  need  not  repeat  it.  For  the 
rest,  time  and  experience  can  alone  make  an 
experienced  engineer.  No  man  can  learn  from 
a  book  exactly  what  to  do  with  an  engine  to 
make  it  perform  to  the  best  advantage. 

We  have  said  nothing  in  this  work  as  to  the 
lubrication  of  an  engine,  but  this  is  an  impor- 
tant matter,  and  should  be  performed  automat- 
ically. No  one  should  use  a  squirt-can  about 
an  engine  except  for  temporary  use.  There 
are  various  devices  in  market  for  feeding  oil  or 
grease  to  engines,  and  most  of  them  are  good. 
Sight  feed  lubricators  are  essential;  no  one  now 
uses  tallow  or  other  animal  fats.  These  last 
destroy  cast-iron  most  rapidly.  We  leave  this 
matter  to  the  discretion  of  those  in  charge. 


CHAPTER   XIII. 

MAKING  JOINTS. 

Joints  about  engines  are,  in  the  best  prac- 
tice, scraped  or  ground  iron  and  iron,  but  in 
most  machines  they  are  made  by  interposing 
sheet-rubber,  or  patented  compositions  of  it, 
which  answer  the  purpose  fully.  Jenkins  Bros., 
of  New  York  city,  make  a  very  good  material 
of  this  kind,  while  for  metallic  joints  under 
high  pressure,  the  corrugated  copper  disks 
made  by  the  Mineral  Wool  Company  of  New 
York  are  unsurpassed.  These  last  can  be  used 
over  and  over  again,  and  will  not  blow  out  or 
leak  under  any  pressure.  Where  it  is  not  pos- 
sible to  obtain  these  goods,  a  very  good  joint 
can  be  made  with  the  wire-cloth  used  for  mos- 
quito-net frames.  Cut  this  to  the  size  required, 
and  make  a  very  thick  paint  with  red  lead  and 
boiled  oil ;  daub  this  over  the  surface  of  the 
cloth  and  screw  it  up  tight;  it  will  never  leak 
or  blow  out,  but  it  will  be  hard  work  to  break 
the  joint  if  it  is  suffered  to  remain  for  a  length 
of  time.  If  no  cloth  is  handy,  a  single  copper 
wire,  say  a  scant  eighth  of  an  inch  in  diameter, 
will  make  a  tight  joint.  Cut  the  wire  the  right 
length,  stick  it  in  a  fire  and  heat  it  red-hot  and 
plunge  it  into  cold  water.  This  will  make  it 
as  soft  as  lead,  so  that  it  will  flatten  under  the 


89 

bolt  pressure  and  fill  all  inequalities  of  surface. 
For  face  joints,  like  steam  chest  bonnets,  hot 
or  cold  water  pipes,  heavy  packing  or  drawing- 
paper  makes  an  excellent  joint.  Soak  it  in 
boiled  oil  and  put  it  right  on  ;  the  heat  will 
harden  it  into  a  parchment-like  substance  which 
is  very  serviceable.  For  permanent  joints,  like 
those  in  water-pipes  under  ground,  or  where 
they  never  have  to  be  broken,  a  rust  joint,  so 
called,  is  the  best.  This  can  be  made  only 
where  the  castings  are  fitted  for  it  in  the  de- 
sign— that  is,  with  a  wide  channel  all  around 
to  receive  the  joint.  A  rust  joint  is  made  of 
fresh,  clean  cast-iron  chips  or  borings  which 
have  no  grease  upon  them.  They  are  mixed 
with  sal-ammoniac  water  and  driven  tightly 
into  the  space  between  the  pipes,  where  the 
borings  soon  rust  into  a  solid  mass.  Putty 
joints,  so  called,  are  used  chiefly  on  cold-water 
pipes,  about  the  feed  pump,  and  may  be  used 
on  hot-water  pipes  as  well,  if  suffered  to  get 
hard  before  being  put  under  heat  and  pressure. 
The  putty  is  made  of  dry  red  lead  and  white 
lead  mixed  with  oil,  kneaded  together  to  a 
stiff  dough.  It  must  be  beaten  with  a  mallet, 
and  the  stiffer  it  is  the  quicker  it  sets.  It  hard- 
ens into  a  mass  as  solid  as  a  brick  in  time. 

All  these  materials  are  only  for  exceptional 
use — that  is,  where  the  usual  rubber  or  other 


9o 

gaskets  can  not  be  had,  for  these  last  are  far 
more  convenient  than  any  just  mentioned.  In 
all  cases  where  rubber  joints  are  used  they 
must  be  chalked  or  rubbed  with  Dixon's  black 
lead ;  this  prevents  them  from  sticking  to  the 
surfaces  in  contact.  Joints  should,  in  all  cases, 
be  made  as  long  before  their  use  as  possible, 
so  as  to  give  them  a  chance  to  set  before 
pressure  is  put  upon  them. 

Packing  the  rods  of  steam  engines  is  a  sim- 
ple matter,  but  simple  as  it  is  it  requires  judg- 
ment and  good  sense.  Like  every  other  duty 
about  a  steam  engine,  it  needs  to  be  properly 
done  in  order  to  work  satisfactorily.  Very 
many  have  an  idea  that  the  packing  in  a  stuff- 
ing box  must  be  jammed  in  as  hard  as  it  will 
go  to  prevent  steam  from  leaking  out,  or  what 
is  just  as  bad,  air  leaking  in  when  condensing 
engines  are  used.  The  reverse  of  this  is  true. 
There  is  no  occasion  to  break  studs  and  strip 
nuts  on  stuffing  boxes  to  make  a  piston  rod 
steam  tight,  but  this  very  thing  has  been  done 
by  inexperienced  persons.  When  a  piston  rod 
of  any  size  can  not  be  kept  steam  tight  by 
moderate  pressure  on  the  packing,  there  is  some- 
thing wrong  with  the  stuffing  box  itself,  and  this 
trouble  in  old  engines,  and  in  some  new  ones, 
too,  will  generally  be  found  in  the  bottom  of 
the  stuffing  box  where  the  rod  passes  through 


the  head.  Too  often  this  opening  is  made  too 
large;  in  the  case  of  old  engines  the  piston  rod 
has  worn  it  oval  by  bearing  on  it.  The  remedy 
is  to  make  a  brass  collar,  or  even  of  lead,  which 
fits  the  piston  rod  nicely,  and  is  one-eighth  of 
one  inch  smaller  than  the  stuffing  box  itself,  or 
so  that  it  is  a  loose  fit.  Put  this  in  the  bottom 
of  the  box,  and  a  few  turns  of  packing  on  top, 
moderately  compressed,  will  keep  the  rods 
tight.  As  to  the  packing  itself,  use  metallic 
packing  where  it  is  possible.  There  is  no  com- 
parison between  it  and  ordinary  hemp  pack- 
ing used  before  there  was  any  metallic  pack- 
ing. This  last  is  always  tight  on  good  rods 
and  runs  with  very  moderate  friction.  It  never 
needs  screwing  up  or  any  other  attention  than 
to  keep  it  in  good  working  order.  When  metal- 
lic packing  can  not  be  had,  an  excellent  sub- 
stitute for  it  can  be  found  in  hemp  gaskets 
braided  firmly  into  a  square,  and  thoroughly 
saturated  with  plumbago;  that  is  blacklead. 
Do  not  make  the  mistake  of  using  stove  polish 
on  gaskets  because  there  happens  to  be  plum- 
bago in  it.  This  quality  is  full  of  grit  from  the 
clay  in  it,  and  will  badly  score  any  rod  to  which 
it  is  applied.  Some  engineers  use  one  thing 
and  some  another.  There  are  various  kinds  of 
packing  in  market  made  from  woven  material, 
india-rubber,  etc.,  etc.,  and  engineers  in  large 


92 

towns  can  have  a  variety  to  select  from.  The 
principal  thing  is,  as  has  been  said,  to  havethe 
stuffing-  box  itself  in  good  order;  then  very 
little  compression  is  needed.  It  would  sur- 
prise many  who  have  never  given  the  matter  a 
thought  to  see  what  resistance  to  motion  a  rod 
two  inches  in  diameter  only,  can  offer  when 
packed  tightly. 


93 


CHAPTER  XIV. 
CONDENSING  ENGINES. 

Thus  far  we  have  given  attention  wholly  to 
engines  which  exhaust  into  the  air,  high  pres- 
sure engines  so  called,  or  those  which  do  not 
condense  the  exhaust.  Condensing  engines  are 
sometimes  called  "low  pressure"  yet,  but  this 
is  a  term  which  is  no  longer  applicable.  It  was 
used  in  the  early  days  of  the  steam  engine, 
when  pressures  were  low,  five  and  six  pounds 
above  the  atmosphere.  As  a  knowledge  of 
boiler  making  increased,  and  higher  pressures 
were  available,  the  condensing  apparatus  was 
discarded  as  costly  and  cumbrous,  and  engines 
were  made  to  exhaust  into  the  air  at  higher 
pressures.  To  distinguish  them  from  condens- 
ing engines,  the  terms  high  pressure  and  low 
pressure  were  used,  but  there  is  no  longer  any 
fitness  in  the  appellation,  for  condensing  en- 
gines will  work  at  any  pressure.  The  chief 
feature,  then,  of  a  condensing  engine  is  that  it 
exhausts  into  a  vacuum  instead  of  against  the 
pressure  of  the  atmosphere.  Every  one  knows 
that  this  last  plugs  up  the  exhaust  pipe  with  a 
pressure  of  14.7  pounds  upon  every  square  inch 
of  its  area.  All  that  the  condensing  engine 
does  is  to  remove  the  plug  and  give  a  free  exit 
to  the  exhaust.  This  is  done  by  creating  a 


94 

vacuum  in  a  closed  chamber  called  a  con- 
denser. Every  one,  even  those  with  little  or 
no  experience,  knows  this,  but  not  all  know 
what  a  vacuum  really  is,  or  why  and  how  such 
a  state  of  things  is  possible.  We  can  not  say  a 
vacuum  exists,  for  it  is  not  a  thing.  It  is,  in 
fact,  nothing;  it  has  no  existence.  A  vacuum 
is  simply  absolute  space,  devoid  of  any  fluid, 
solid  or  gas.  It  can  be  obtained  in  two  ways: 
by  mechanically  pumping  the  air  out  of  any 
tight  vessel,  or  by  admitting  steam  to  it  and 
throwing  cold  water  in  upon  the  steam.  With 
steam  engines  this  is  the  usual  way  to  obtain  a 
vacuum"  and  the  philosophy  of  it  is  very  easily 
understood  by  what  follows:  Suppose  we  have 
a  cubic  inch  of  water;  that  is  a  block  of  water 
one  inch  square  every  way.  Now,  if  we  change 
this  into  boiling  water  (212°),  and  let  the  steam 
from  it  into  a  tight  chamber  one  foot  every 
way,  the  steam  will  fill  the  chamber  and  be  at 
atmospheric  pressure  in  it.  Now,  if  we  have  a 
pipe  to  this  chamber,  and  run  cold  water  in  so 
that  it  strikes  the  steam  in  a  spray,  the  steam 
will  be  condensed  and  fall  to  the  bottom  in  the 
form  of  water  again,  the  air  and  condensed 
steam  falling  together.  Above  this  water 
there  is  a  vacuum  more  or  less  perfect;  but  to 
make  it  an  absolute  vacuum  we  must  remove 
the  water  of  condensation  and  whatever  air 


95 

there  is  remaining.  To  do  this  a  pump  is 
necessary,  and  it  is  always  present  in  con- 
densing engines.  It  is  called  an  air  pump,  and 
in  action  it  removes  the  air  and  water  of  con- 
densation from  the  condenser,  leaving  a  more 
or  less  perfect  vacuum,  into  which  the  engine 
exhausts.  This  operation  goes  on  continually; 
the  engine  is  always  exhausting  into  the  con- 
denser, the  cold  water  is  always  condensing 
the  steam,  and  the  air  pump  is  constantly  re- 
moving the  water  and  mist  held  in  suspension. 
To  some  this  operation  is  a  very  complicated 
one,  and  many  engineers  say  they  can  readily 
manage  a  high  pressure  engine,  but  do  not 
know  anything  about  a  condensing  engine. 
There  is  no  reason  why  they  should  not  un- 
derstand the  one  as  well  as  the  other,  for  there 
is  nothing  in  a  condensing  engine  beyond  the 
capacity  of  every  intelligent  man.  The  two 
evils  to  be  guarded  against  in  a  condensing  en- 
gine are  air  leaks  and  heat  in  the  condenser. 
Look  out  for  these,  and  there  will  be  no  trouble 
in  maintaining  a  vacuum. 

Since  we  have  seen  that  a  vacuum  is  abso- 
lute space,  it  is  plain  that  if  air  leaks  are  pres- 
ent the  vacuum  will  be  impaired  to  just  the 
amount  that  the  air  leaks  in  beyond  the  capa- 
city of  the  air  pump  to  remove  it.  If  the  con- 
denser is  not  cold  the  steam  will  not  be  con- 


96 

densed  quickly,  and  if  the  water  of  condensa- 
tion and  the  vapor  are  not  also  removed,  there 
will  only  be  a  partial  vacuum,  for  the  water  of 
condensation  is  not  absolutely  cold,  but  at  120 
to  140  degrees,  and  gives  off  vapor  which  also 
injures  the  vacuum.  This  is,  in  as  few  words 
as  possible,  the  detail  of  a  condensing  engine, 
and  it  does  not  seem  a  formidable  affair. 
There  are  two  kinds  of  condensers  in  general 
use — the  jet  or  absolute  contact  condenser, 
and  the  surface  or  indirect  acting  condenser. 
The  first  is  simply  a  cast-iron  vessel,  usually 
round,  as  best  adapted  to  resist  the  pressure  of 
the  atmosphere,  for  it  must  be  remembered 
that  the  pressure  on  a  condenser  outside  is 
many  tons  in  the  aggregate.  (A  condenser 
only  40"  diameter  and  72"  long,  under  a  perfect 
vacuum,  has  over  37^  tons  total  pressure  on 
the  outside,  tending  to  crush  it.)  Into  this 
vessel  cold  water  is  run  through  a  perforated 
nozzle;  when  the  water  strikes  the  steam  the 
latter  is  condensed  and  both  the  injected  water 
and  the  condensed  steam  fall  to  the  bottom  of 
the  vessel.  The  surface  condenser  is  exactly 
the  same  as  a  common  tubular  boiler.  The 
steam  enters  outside  of  the  pipes  (or  flues)  and 
the  condensing  water  goes  through  them.  The 
exhaust  steam,  therefore,  does  not  strike  the 
water  directly,  but  is  merely  received  upon  a  cold 


97 

surface,  and  the  water  of  condensation,  only, 
falls  to  the  bottom  of  the  condenser;  the  con- 
densing water  passes  away  constantly  through 
the  pipes,  or  flues,  and  does  not  mingle  with 
the  condensing  steam.  This  method  gives  ab- 
solutely pure  water  for  the  boiler  feed,  except- 
ing only  the  foreign  matters  which  may  enter 
with  the  steam.  Surface  condensers  are  used 
chiefly  upon  ocean  steamers,  where  they  are 
indispensable,  as  they  furnish  fresh  water  for 
the  boilers.  In  long  voyages  they  are  a  neces- 
sity, and  the  greatest  care  is  taken  to  avoid 
steam  leaks,  for  this  means  a  reduced  supply 
to  the  boilers,  Surface  condensers  also  supply 
an  immediate  vacuum  at  the  first  exhaust  of 
the  engine.  A  circulating  pump  keeps  cold 
water  going  through  the  tubes  constantly,  so 
that  as  soon  as  the  exhaust  steam  strikes  it  it  is 
condensed,  and  the  main  engines  'Hake  hold," 
as  it  is  called.  This  is  not  always  the  case 
with  a  jet  condenser,  in  which  the  vacuum  is 
not  very  good  for  two  or  three  revolutions.  A 
vacuum  is  a  vacuum,  however  obtained,  and  so 
long  as  one  is  produced  that  is  the  main  thing. 
A  loss  of  it  is  a  loss  of  power,  for  the  resistance 
of  the  atmosphere  being  removed  from  the  ex- 
haust side,  the  weight  of  it  is  added  to  the  pres- 
sure on  the  piston.  Thus,  if  the  steam  gauge 
shows  seventy-five  pounds,  the  actual  or  abso- 
7 


98 

lute  pressure  is  75x15,  or  Qb'pounds.  From 
this  aspect  we  can  readily  see  why  engineers 
are  sensitive  about  the  condition  of  the  vac- 
uum, whether  it  is  full  or  only  partial. 

The  first  mechanically  made  vacuum  of 
which  we  have  any  authentic  record  is  that  of 
Torricelli,  an  Italian  experimenter,  and  of  Otto 
Guericke,  a  German  experimenter.  Which  of 
these  was  the  pioneer  vacuum  maker  history 
saith  not.  Otto  Guericke,  of  Madgeburgh, 
Germany,  invented  the  common  air  pump,  used 
in  philosophical  experiments,  in  1654.  He  first 
tried,  by  filling  a  barrel  full  of  water  and  pump- 
ing out  the  contents  from  the  bottom,  to  obtain 
a  vacuum  above  the  water,  but  the  barrel  was 
not  air  tight  and  the  experiment  failed.  He 
then  made  an  ordinary  metallic  pump  and  ob- 
tained a  vacuum.  To  show  that  air  was  a  fac- 
tor in  the  work  of  the  world,  and  that  we  are 
surrounded  by  an  atmosphere  under  pressure, 
he  made  a  pair  of  brass  hemispheres,  which 
had  a  ground  joint  in  the  center  and  a  cock  in 
the  stand  at  the  bottom  of  them.  He  connect- 
ed his  air  pump  to  these,  and  exhausted  the 
air  from  the  globe,  and  then  hitched  fifteen 
horses  to  an  eyebolt  in  the  upper  hemisphere, 
but  they  were  unable  to  pull  the  upper  half  off 
of  the  lower.  This  demonstrated  conclusively 
that  the  atmosphere  had  pressure,  for  upon 


99 

opening  the  cock  and  letting  air  into  the  hem- 
ispheres again,  the  balance  was  restored  and 
the  hemispheres  fell  apart.  The  first  actual 
measure  of  the  weight  of  the  atmosphere  is  due 
to  Torricelli,  also  about  the  middle  of  the  seven- 
teenth century. 


I  DO 


CHAPTER   XV. 
TORRICELLI'S  VACUUM. 

This  was  by  reason  of  a  suggestion  from  the 
Duke  of  Tuscany,  who,  having  dug  a  very  deep 
well,  proceeded  to  pump  it  out.  He  found, 
however,  that  he  could  not  raise  water  over  32 
feet,  and  he  must  have  had  a  pretty  good  pump 
to  do  that.  Not  succeeding  in  getting  water 
the  Duke  consulted  Galileo,  the  famous  philos- 
opher who  discovered  the  motion  of  the  earth. 
This  water  problem  was  too  much  for  him,  and 
he  gave  it  up.  Shortly  before  Galileo  died  he 
gave  the  puzzle  to  Torricelli,  who  began  to 
work  with  mercury  as  a  basis  of  comparison  of 
the  relative  weights  of  the  pressure  of  the  at- 
mosphere. Now  mercury  is  fourteen  times 
the  weight  of  water,  and  Torricelli  argued  that 
if  the  atmosphere  would  support  a  column  of 
water  32  feet  high  (as  it  was  proven  it  would 
in  the  case  of  the  pump  before  referred  to),  it 
would  also  support  a  column  of  mercury  one- 
fourteenth  the  height  of  the  water,  or  28  inches. 
To  test  this  he  took  a  glass  tube,  sealed  at  one 
end,  and  rilled  it  full  of  mercury,  displacing  all 
the  air  therein.  He  then  closed  the  open  end 
with  his  finger  and  inverted  the  tube  in  a  basin 
of  mercury,  when  the  mercury  in  the  tube  fell 
and  settled,  as  he  supposed  it  would,  at  28 


IOI 

inches,  leaving  a  vacuum  in  the  upper  part. 
Torricelli  did  not  live  long  enough  to  do  much 
with  his  discovery,  but  another  philosopher,  a 
Frenchman,  Pascal  by  name,  took  it  up  and 
carried  the  experiments  further.  It  occurred  to 
him  that  if  at  the  surface  of  the  earth  the  at- 
mosphere supported  a  column  of  water  32 
feet  high,  at  great  elevations  from  the  surface 
it  would  not  support  so  much,  because  the  at- 
mosphere is  rarer,  or  less  dense;  sb"  he  "took 
the  mercury  column  up  on  a 'high  mour'ta'in. 

PROOF  OF  ATMOSPHERIC  PRESSURE. 

At  the  top  it  registered  only  25  inches,  while 
at  the  bottom  it  was  28  inches.  At  other  levels 
between  the  bottom  of  the  mountain  and  its 
top  he  found  varying  registers  on  the  mercury 
column,  so  it  is  established  by  inductive  rea- 
soning, supported  by  experiments,  that  at  the 
surface  of  the  earth  water  will  rise  in  a  perfect 
vacuum  32  feet,  supported  of  course  by  the 
pressure  of  the  atmosphere,  for  the  vacuum  it- 
self has  no  power  whatever;  it  is  as  stated. pre- 
viously, merely  a  space  which  offers  no  resist- 
ance, therefore,  water  or  air  rushes  in  to  fill  it. 
No  POWER  IN  A  VACUUM. 

It  is  important  for  engineers  to  know  these 
facts  because  there  are  still  a  great  many  who 
are  not  aware  of  them,  and  suppose  that  a  vac- 


102 

uum  has  some  power  in  itself  or  that  it  has  an 
existence  as  a  force  because  it  is  measured  on 
a  gauge.  This  last  is  an  error.  Vacuum  is  not 
measured  on  a  gauge.,  but  atmospheric  press- 
ure is.  We  can  not  measure  a  nonentity  and 
we  must  insist  that  engineers  bear  in  mind  that 
a  vacuum  is  just  that ;  it  is  nothing  but  space. 
Space  has  neither  weight,  dimension,  nor 
boui'jdaiyj  'if  is  infinity. 

Suppose  'the  vacuum  gauge  shows  26  inches, 
v/tiai  t'Oes  thai  mean  ?  It  does  not  mean  that 
there  is  a  space  of  26  inches  in  1he  condenser 
which  has  no  air  in  it,  or  that  there  are  26 
inches  of  space  in  the  cylinder  which  is  a  vacu- 
um; it  means  that  there  is  nearly  an  absence  of 
air  in  the  condenser,  since  the  pressure  of  the 
atmosphere  has  forced  the  gauge  index  around 
to  the  26  inch  mark.  Now,  26  inches  repre- 
sent 13  pounds  air  pressure,  so  we  might  just 
as  well  (perhaps  better)  mark  vacuum  gauges 
by  pounds  as  by  inches.  The  first  vacuum 
gauges,  however,  were  mercurial  tubes  on  the 
Torricellian  principle,  and  were  marked  in  in- 
ches, so  this  system  is  still  kept  up.  Suppose  the 
vacuum  gauge  shows  only  20  inches;  then 
there  is  a  partial  vacuum  only,  for  20  inches  are 
equal  to  10  pounds  only,  and  with  the  vacuum 
gauge  at  20  inches  there  are  four  pounds  press- 
ure in  the  condenser,  a  dead  loss  to  us,  for  we 


io3 

are  working  against  so    much  back   pressure 
when  there  should  not  be  any. 

Now,  the  best  vacuum  we  can  get  with 
modern  appliances  and  at  the  speed  we  run 
engines  in  these  days  is  26  to  27  inches,  rarely 
the  latter.  This  loss  of  one  pound  is  due  to  the 
want  of  time  to  remove  the  last  vestige  of  air 
and  vapor,  to  the  mechanical  imperfections  of 
our  appliances,  and  to  the  fog  or  mist  of  con- 
densation, which  to  a  greater  or  less  extent 
pervades  all  condensers,  whether  surface  or 
jet.  It  is  creditable  that  we  are  able  to  do  so 
much  as  this,  but  the  greatest  enemy  engineers 
have  to  contend  with  in  maintaining  a  vacuum 
is  air  leaks,  pure  and  simple.  The  joints  about 
a  condensing  engine  are  almost  innumerable, 
and  each  pinhole,  even,  contributes  its  quota 
of  mischief.  Leaks  occur  through  bolt  holes, 
through  gaskets,  through  castings  themselves. 
The  chaplets  used  in  foundries  to  support  cores 
are  very  liable  to  be  leaky.  Look  out  for  them, 
and  daub  them  over  thickly  with  red  lead  paint. 
Paint  every  part  of  the  injection  pipes  thickly; 
keep  all  stuffing  boxes  of  injection  valves  well 
packed  and  use  every  means  you  can  think  of 
to  guard  against  loss  of  atmospheric  pressure 
by  leakage  of  air  into  the  condenser.  Go  round 
to  every  joint  you  can  reach  with  a  lamp  and 
hold  the  flame  against  it.  If  there  are  air  leaks  you 


IO4 

can  sometimes  hear  them,  but  when  too  small 
to  be  heard  they  can  be  seen,  for  the  flame 
will  be  forced  in  toward  the  leak.  Keep  the 
foot  valves  in  perfect  order,  and  the  air-pump 
bucket  as  well,  both  must  be  as  near  air  tight 
as  possible.  Remember  the  adage  :  "Nature 
abhors  a  vacuum1  and  will  fill  it  in  an  incredibly 
short  time  if  she  is  not  prevented. 

If,  when  the  engine  is  working  well  other- 
wise, the  vacuum  begins  to  fall,  so  to  call  it, 
give  more  injection  water.  Sometimes  steam 
from  the  boiler  is  hotter  than  at  others,  the 
water  in  the  boiler  falls  and  the  steam  is  super- 
heated; that  calls  for  more  injection.  If  the 
vacuum  is  still  poor  try  the  condenser  by  hand 
and  if  it  is  warm  and  getting  warmer,  and  no 
amount  of  injection  water  will  keep  cool,  see 
if  the  foot-valves  seat  properly.  If  they  are 
cocked  ever  so  little  the  water  of  condensation 
can  not  get  out,  and  by  lying  in  the  bottom  of 
the  condenser  kills  the  vacuum  with  its  vapor. 
The  injection  pipes  may  also  be  stopped.  In 
fresh  water,  eels  often  get  drawn  into  the  pipes 
and  stop  them,  when  the  water  is  drawn  from 
ponds  ;  in  rivers  and  streams,  weeds,  and  also 
fish,  get  drawn  across  the  strainer  and  prevent 
the  water  from  entering.  Every  injection  pipe, 
whether  on  sea  or  on  shore,  should  have  a 
steam  pipe  let  into  it  for  use  in  emergencies, 


io5 

with  a  nozzle  pointing  toward  the  source  of 
supply.  It  may  save  a  long  stop  for  cleaning 
the  water  pipe. 

A  good  vacuum  is  worth  13  pounds  of  steam 
in  the  boiler,  and  the  feed  water  is  heated  to 
1 20  degrees  without  charge  for  the  same.  All 
it  costs  is  the  extra  machinery  needed  to  obtain 
it,  an  air  pump,  injection  valve,  and  pipes  and 
details.  This  once  paid  for  is  a  small  expense 
to  maintain,  so  that  for  a  term  of  years  the 
outlay  for  a  condensing  engine  is  soon  made 
up  in  the  decreased  cost  per  horse  power  per 
hour.  That  condensing  engines  are  not  more 
frequently  employed  is  due  to  the  belief  on  the 
part  of  the  steam  users  that  they  are  complicat- 
ed, costly  to  maintain  and  hard  to  manage. 
The  exact  reverse  of  this  statement  is  the  cor- 
rect one. 

PUMPS. 

The  popular  idea  is  that  a  pump  has  some- 
thing to  do  with  raising  water  or  oil,  or  mo- 
lasses, or  any  other  fluid  it  may  happen  to  be 
at  work  upon,  but  this  is  a  gross  error,  first 
pointed  out  in  the  pages  of  THE  ENGINEER. 
By  reason  of  this  view,  persons  who  run  pumps 
are  very  often  troubled  about  the  water  which 
comes  to  the  pump,  and,  in  case  of  failure  of 
the  pump  to  act,  they  examine  into  the  con- 
dition or  connections  to  the  water,  as  if  these 


io6 

had  something  to  do  with  the  difficulty.  The 
only  thing  which  can  prevent  a  pump  from 
working  is  air,  and  air  leaks  on  the  suction 
side  and  force  side,  so-called.  Actually  there 
is  no  suction  side,  neither  is  there  any  such 
force  exerted  as  suction.  It  is  a  term  invented 
and  applied  long  before  we  knew  what  atmos- 
pheric pressure  was,  or  recognized  its  great  in- 
fluence in  the  work  of  a  steam  engine.  The 
sole  office  and  function  of  a  lifting  pump — so- 
called — is  to  remove  the  air  from  the  pipe 
which  conveys  the  water  to  the  pump.  When 
this  is  done  water  flows  to  the  pump  by  the 
pressure  of  the  atmosphere  outside  upon  it, 
forcing  it  up  to  the  pump  chambers.  If  the  air 
is  completely  exhausted  the  water  enters  freely 
and  the  pump  is  said  to  work  well.  If  it  is 
only  partly  exhausted  the  water  flows  slug- 
gishly, and  the  pump  works  badly.  If  we  need 
proof  that  a  pump  has  no  direct  effect  on  the 
water  itself,  we  can  attach  one  to  a  pipe  36  feet 
long.  The  water  will  then  rise  in  the  pipe  for 
32  feet,  but  after  this  occurs  we  may  work  the 
pump  for  all  time  and  not  get  a  particle  of  water 
through  it.  The  reason  of  this  is  that  the  at- 
mosphere will  not  support  a  column  of  water 
over  32  feet  in  height,  and  therefore  the  pump 
has  no  effect  upon  it. 


ioy 


CHAPTER  XVI. 
SUPPORTING  A  WATER  COLUMN  BY  THE  ATMOSPHERE. 

Now  there  are  many  who  do  not  understand 
clearly  what  is  meant  by  the  atmosphere  sup- 
porting a  column  of  water.  They  see  a  pipe 

B 


Fig.  23 

full  of  water — a  stand-pipe,  for  instance — which 
is  merely  along  tank  upon  end;  or  they  see  a 
tank  at  a  railway  station,  and  understand  that 
these  are  not  supported  by  the  atmosphere,  but 
are  merely  reservoirs  which  have  been  filled 


io8 

up.  Where,  then,  is  the  difference  ?  The  dia- 
gram appended  will  make  this  plain.  This  is 
all  pipe,  34  feet  long  from  its  base  at  A  to  its 
top  B.  Now,  suppose  we  fill  this  pipe  up  to 
the  mark  <7,  or  any  other  mark  equal  to  half 
the  capacity  of  the  pipe,  and  attach  a  pump  at 
B,  keeping  it  air-tight.  When  we  exhaust  the 
air  from  the  arm  D  the  pressure  of  the  atmos- 
phere in  the  arm  E  will  drive  the  water  up  in 
D  say  33  feet,  if  there  is  a  perfect  vacuum,  and 
the  water  will  stand  there  just  so  long  as  the 
vacuum  is  maintained,  no  longer,  unless  there 
is  a  valve  at  the  bottom  to  prevent  its  return. 

If  the  pump  is  stopped  the  water  will  fall 
to  its  level  again,  because  air  gets  in  through 
the  pump  and  restores  the  balance.  If  there 
was  no  vacuum  the  water  would  stand  at  the 
same  height  in  both  arms,  because  there  is 
just  as  much  atmospheric  pressure  on  one 
side  of  it  as  on  the  other  side,  and  water  be- 
ing heavier  than  air,  finds  its  level.  This  is 
all  the  mystery  there  is  in  the  operation  of 
a  pump  of  any  kind  whatever,  and  aside 
from  the  mechanism  which  drives  it  if  a  well 
pump  will  not  perform  as  it  should,  the  reason 
can  be  generally  found  on  the  suction  side  so- 
called  ;  the  plunger  or  bucket  does  not  remove 
the  air  so  that  the  water  can  get  in.  It  is  easy 
to  see,  then,  that  a  pump  demands  the  very 


109 

best  workmanship  in  all  its  interior  working 
parts.  The  barrel  should  be  smooth  and  true 
if  a  bucket  works  in  it,  and  the  packing  of  the 
same  should  be  tight.  If  it  is  a  plunger-pump, 
where  the  plunger  is  clear  of  the  barrel,  the 
stuffing  box  should  be  long,  well  packed,  and 
the  plunger  itself  should  be  true  and  work  true 
in  its  path.  Suspect  every  joint  on  the  suction 
side  of  leaking,  and  if  there  are  screw  bolts 
which  go  through  castings  on  the  suction  side 
suspect  them  also  ;  a  good  deal  of  air  can  get 
in  through  a  very  small  opening.  If  there  are 
many  of  these  the  net  result  detracts  from  the 
work  of  the  pump.  Friction  of  water  is  an- 
other element  against  a  pump.  This  in  the  ag- 
gregate is  very  great  in  long  pipes  and  in  tor- 
tuous passages.  Elbows  and  rough  castings 
can  take  off  much  from  the  efficiency  of  a  pump 
where  the  water  has  to  be  forced  to  it  for  long 
distances  by  the  atmosphere,  and  this  must  be 
considered  in  the  erection  of  any  plant.  There 
are  only  14.7  pounds  pressure  on  ihe  water 
outside  to  get  it  where  we  want  it,  and  this 
only  when  we  have  a  perfect  vacuum  in  the 
pipes  ;  with  an  imperfect  one  we  have  much 
less  pressure.  All  this  relates  to  what  is  known 
as  the  suction  side  of  a  pump,  but,  on  the  forc- 
ing side  it  is  just  as  bad  if  the  pipes  run  in- 
directly. All  feed  pipes  should  go  as  straight 


110 

as  they  can  be  run  to  the  boiler,  but  sometimes 
it  is  not  possible  to  do  this,  and  loops  and  vei> 
tical  bends  are  made  in  them.  Air  collects  in 
the  tops  of  these  bends  and  stops  the  water 
quite  as  effectually  as  a  block  of  wood  could. 
It  lies  on  top  of  the  water  as  wood  floats  on  it, 
because  it  is  very  much  lighter,  and  is  com- 
pressed so  much  by  the  action  of  the  plunger 
that  it  resists  the  main  flow  of  the  current,  and 
the  water  surges  back  and  forth  in  the  cham- 
bers. This  is  fully  shown  in  an  air  chamber, 
which  is  a  well  known  adjunct  to  pumps,  both 
single  and  double-acting.  If  metal  valves  are 
used  for  the  lift  or  force  sides,  they  should  be 
carefully  examined,  from  time  to  time,  to  see 
that  they  are  tight  on  their  seats,  and  lift 
squarely,  and  seat  fairly.  An  unsuspected 
source  of  trouble  is  often  found  in  the  seats  of 
valves.  These  last  are  brass  bushes  driven  into 
cast-iron  chambers.  Sometimes  these  cham- 
bers are  bored  out  for  the  valve  seats,  and  very 
often  they  are  not,  but  taken  as  they  come  from 
the  foundry.  In  work  of  this  character  it  is  not 
uncommon  to  find  leaks.  The  seats  also  work 
loose  in  the  castings,  and  leak  from  that  cause. 
Another  difficulty  with  pumps  is  found  in  the 
lift  or  rise  given  the  valves.  Quick  working 
pumps  require  very  little  lift  to  the  valves  on 
either  side,  but  the  most  should  be  given  on 


Ill 

the  force  side.  Divide  the  diameter  of  the 
Valve  by  four;  this  will  give  a  lift  equal  to  the 
area  of  the  opening  in  the  valve  seat,  which  is 
all  that  can  be  delivered  to  the  pump  barrel. 
A  two  inch  valve,  then,  should  lift  only  half 
an  inch,  and  even  this  will  be  found  too  much 
in  some  cases.  Plunger  pumps  that  run  at  high 
speed,  or  over  100  feet  per  minute,  are  very  apt 
to  pound  violently  and  make  a  great  deal  of 
noise.  This  can  be  overcome  wholly  by  sim- 
ply coning  the  end  of  the  plunger  to  an  angle 
of  30  or  40  degrees.  Put  the  plunger  in  a  lathe 
and  bevel  the  end  off,  and  there  will  be  no  more 
pounding.  The  reason  for  this  is  not  easy  to 
find.  Pumps  are  still  used  in  many  places  for 
feeding  boilers,  but  in  a  majority  of  cases  in- 
jectors are  used.  These  last  are  simply  man- 
aged, and  the  fullest  directions  are  sent  with 
them  by  the  manufacturer.  If  they  are  follow- 
ed implicitly  there  will  be  no  trouble,  but  if 
persons  undertake  experiments  on  their  own 
account  they  must  not  blame  the  apparatus. 

These  are  succinctly  the  principles  govern- 
ing the  action  of  condensing  engines  and  the 
pumps  by  which  they  are  worked.  All  pumps 
act  upon  the  same  principles  as  those  previ- 
ously alluded  to.  Whether  the  detail  which  ex- 
hausts the  air  from  the  water  supply  pipes  is  a 
scroll,  a  screw,  or  a  fan  attached  to  a  shaft  and 


112 

rotated  by  it,  as  in  a  centrifugal  pump,  whether 
it  is  a  simple  bucket  or  a  plunger,  the  fact  is  the 
same:  the  air  must  first  be  removed  before  any 
water  can  get  to  the  pump,  and  the  special  de- 
tail, the  fan  aforesaid,  or  the  bucket  or  plunger 
which  forces  the  water  out  of  the  pump  cham- 
ber has  no  direct  influence  upon  drawing  the 
water  itself.  It  may-be  that  we  have  reiterated 
this  too  often,  but  we  think  not,  in  view  of  the 
fact  that  we  were  told  quite  recently  by  a  per- 
son in  charge  of  a  pump  that  the  suction 
valves  were  so  heavy  that  the  plunger  could  not 
lift  them.  It  is  very  hard  to  get  rid  of  notions 
and  ideas;  the  more  erroneous  they  are  the 
more  difficult  it  is  to  abandon  them.  This  is 
our  apology,  if  any  is  needed,  for  insisting 
upon  the  facts  laid  down  as  regards  the 
action  of  pumps.  Also,  let  us  say  here,  that  in 
previous  chapters  we  have  stated  that  water 
would  rise  only  32  feet  in  a  pipe  in  a  perfect 
vacuum.  We  should  have  said  in  a  working 
vacuum,  which  is  far  from  being  a  perfect  one. 
The  mean  pressure  of  the  atmosphere  within 
its  known  limits  is  14.7  pounds  per  square  inch, 
which  corresponds  to  a  column  of  mercury 
(supports  it)  29.9  inches  high,  or  will  support  a 
water  column  33.9  feet  high  at  the  sea  level. 
These  are  the  exact  figures,  but  we  have  all 
along  in  this  work  preferred  to  deal  with  every 


day  results  and  figures,  rather  than  submit  mere 
cut  and  dried  recitals  of  tabulated  details. 

Dismissing  the  steam  engine  and  its  belong- 
ings, with  the  bare  review  of  its  functions  and 
management  which  has  been  possible  in  the 
assigned  limits  of  this  work,  and  assuming  that 
we  have  a  new  plant  to  start  for  the  first  time, 
let  us  mention  some  details  that  are  of  great  im- 
portance. 


114 


CHAPTER  XVII. 

STARTING  A  NEW  PLANT. 

New  engines  and  boilers  should  be  started 
with  great  care;  this  statement  applies  particu- 
larly to  the  boiler.  If  the  latter  is  large,  the 
fire  under  it  should  be  started  at  least  three 
days  before  the  boiler  is  actually  needed  for 
work,  and  the  fire  should  be  very  small  indeed 
at  first.  For  the  first  day  no  attempt  should  be 
made  to  raise  steam,  and  the  fire  should  not  be 
urged  in  the  least.  The  water  should  be  al- 
lowed to  get  "hand-warm"  only,  and  be  kept 
at  this  temperature  for  twenty-four  hours.  The 
reasons  for  this  must  be  apparent  with  very 
little  thought.  Everything  is  cold  on  the  start, 
and  all  the  dimensions  will  be  greatly  changed 
by  heat,  and  unless  great  care  is  taken  at  the 
outset  much  injury  can  be  done  to  the  brick 
work  setting  and  the  boiler  itself. 

For  the  second  day  the  temperature  may  be 
increased  to  nearly  the  boiling  point,  but  the 
fire  should  not  be  driven.  The  furnace  doors 
must  be  kept  shut  all  the  time,  and  the  ash-pit 
doors  also,  the  amount  of  draught  and  of  fuel 
being  governed  so  as  to  keep  the  boiler  from 
making  steam.  On  the  third  day  the  boiler 
may  be  allowed  to  make  steam,  but  the  pres- 
sure must  be  brought  up  gradually,  and  the  fire 


H5 

upon  no  account  forced.  The  furnace  doors 
must  be  always  kept  closed  as  before.  As  the 
pressure  rises  above  the  atmosphere,  open  all 
the  steam  connections  and  allow  the  steam  to 
warm  the  pipes  thoroughly  before  putting 
greater  pressure  upon  them.  Do  not  close  any 
valve  with  a  rush  when  the  pressure  rises  to  the 
working  point. 

The  boiler  should  be  full  of  water  on  the 
start,  three  full  gauges,  so  that  while  the  pres- 
sure is  still  low  the  boiler  can  be  blown  down 
— through  the  blow-cock — to  get  rid  of  all  the 
rubbish  that  has  accumulated  in  inaccessible 
corners.  Open  the  blow-cock  steadily,  not 
with  a  twitch  of  the  handle,  and  blow  down  to 
two  gauges.  This  should  not  be  done  until  a 
few  minutes  before  starting  the  engine;  the  feed 
will  not  be  needed  for  a  few  minutes  then,  and 
in  that  time  all  the  feed-pipe  connections  will 
warm  up  and  expand  equally. 

Try  all  movable  joints,  handles,  cocks,  safety 
valves,  everything  in  short,  to  see  if  they  work 
properly,  and  examine  every  valve  and  stuffing 
box  personally  to  see  if  they  have  been  packed 
properly.  Look  carefully  to  all  the  joints  un- 
der pressure,  and  do  all  this  before  a  working 
pressure  is  raised;  keep  up  this  inspection  from 
time  to  time  as  the  pressure  increases.  On 
starting  the  engine,  open  all  the  cylinder  cocks 


to  blow  out  the  condensed  water  which  has 
accumulated  in  the  pipes  and  cylinder.  This 
is  imperative,  not  only  to  get  rid  of  the  con- 
densed water,  but  to  blow  out  the  sand,  chips 
and  minute  filings,  that  can  be  removed  in  no 
other  way.  These  have  accumulated  in  the 
engine  while  it  was  being  built  and  erected, 
and  in  no  other  way  can  they  be  so  effectually 
removed.  Move  the  live  steam  valves,  so  that 
steam  is  blown  through  both  ends  of  the  cylin- 
der for  the  purpose  mentioned. 

Before  turning  the  engine  over  the  center  for 
the  first  time  make  absolutely  sure  that  every- 
thing is  clear  ;  give  the  engine  steam  easily, 
and  run  the  crank  over  on  the  three-quarter 
position;  then  give  steam  the  other  way,  if 
there  is  hand  gear  which  admits  of  it,  and  drive 
the  crank  back  again.  Do  this  carefully,  and 
before  the  engine  is  finally  allowed  to  pass  the 
center  shut  the  throttle  entirely,  so  that  if  any- 
thing is  wrong  or  anything  carries  away,  the 
mischief  will  be  confined  to  one  stroke.  The 
flywheel  will  carry  the  engine  over  the  center. 

An  engine  should  be  started  the  first  time 
under  very  moderate  pressure ;  five  pounds 
should  be  enough  if  the  engine  is  properly 
made.  No  power  is  needed,  and  the  only 
points  to  be  established  are,  whether  every- 
thing is  in  apparent  good  working  order. 


If  possible,  do  not  lace  any  main  belts 
until  after  the  engine  has  been  tested.  There 
is  no  knowing1  what  may  have  to  be  done, 
for  mistakes  are  possible  to  all  until  the  en- 
gine has  been  tried.  If  indicator  attachments 
are  on,  take  friction  diagrams  at  this  time 
with  the  unloaded  engine,  and  see  what  it 
requires  to  move  itself.  Do  the  same*  when 
the  main  belts  and  shafting  are  on.  without 
the  machines,  and  valuable  data  will  be  had 
for  future  reference.  As  to  the  engine  con- 
nections, the  main  bearings,  crank-pin,  and 
cross-head  end,  should  be  left  perfectly  easy. 
If  they  thump  slightly,  it  does  not  matter  when 
the  engine  is  running  slowly.  Thumping 
from  loose  connections  is  very  different  in 
sound  from  pounding  for  want  of  proper  ad- 
justment, and  the  careful  and  experienced 
engineer  will  detect  the  difference  at  once. 

In  all  that  has  been  said,  we  have  endeavor- 
ed to  inculcate  the  idea  that,  above  all  other 
things,  the  most  watchful  care  and  supervision 
is  needed  on  first  starting  a  new  engine  and 
boiler.  On  such  occasions  a  tremendous 
change  is  introduced.  Cold  metal  is  made  hot, 
and,  in  this  transition  alone,  inconceivable 
force  is  generated.  It  is  none  the  less  power- 
ful because  it  is  invisible,  and  makes  itself 
known  only  by  rupture.  Boilers  are  made 


n8 

leaky  by  careless  handling  on  the  start  which 
were  perfectly  tight  and  well  made,  and  strains 
are  set  up  within  them  by  forcing  them,  which 
materially  affects  their  life.  The  same  is  true 
of  the  brick-work,  if  the  boiler  is  so  set,  and  it 
is  for  this  latter,  primarily,  that  we  advised 
three  days  moderate  heating  of  the  boiler  upon 
starting  it.  It  takes,  or  should  take,  a  long 
time  to  heat  a  brick  wall  alike — so  that  it  all 
goes  together,  and  three  days  is  none  too  long. 
If  these  directions  are  followed,  properly 
built  engines  and  boilers  will  perform  well 
from  the  start.  There  will  be  no  running  back 
and  forth  to  the  shop,  or  calking  leaks,  re- 
making joints,  or  any  sort  of  fuss.  There  will 
be  that  harmonious  straight-avvay  condition  of 
affairs  which  mark  the  difference  between  a 
man  who  knows  his  business  and  one  who  does 
not. 

From  what  has  been  said  in  preceding  pages 
it  is  apparent  that  to  be  a  successful  engineer 
requires  care  and  skill  of  the  highest  quality. 
The  attention  necessary  to  keep  a  steam  plant 
up  to  its  best  condition  all  the  while  must  be 
unremitting,  otherwise  great  loss  results.  It 
does  not  follow  from  this  that  an  engineer 
should  be  hopping  around  from  engine  room 
to  fire  room,  or  running  here  and  there  with  a 
squirt  can,  or  in  a  fuss  generally ;  what  we 


mean  to  inculcate  is  that  an  engineer  should 
keep  the  run  of  his  plant  in  his  head  at  all 
times,  and  not  suppose  things  are  all  right 
because  no  accident  has  happened.  Accidents 
never  happen  to  careful  men  ;  they  only  happen 
to  persons  who  suppose  instead  of  knowing, 
as  far  as  human  foresight  can  go.  Mysterious 
boiler  explosions,  mysterious  flywheel  burst- 
ing, mysterious  anythings  about  steam  engines, 
could,  if  all  the  facts  were  known  and  the 
naked  truth  were  told,  be  traced  to  a  condition 
of  things  previously  known  to  some  one  which 
was  willfully  neglected.  "Let  well  enough 
alone,"  is  a  good  maxim  in  an  engine  room, 
but  this  does  not  mean  that  bearings  are  never 
to  be  examined,  boilers  never  cleaned,  or  never 
examined  for  defective  braces,  and  the  whole 
routine  of  an  engineer's  duties  neglected.  For 
ten  hours  daily,  at  the  least,  an  engineer  must 
keep  watch  of  his  engine  and  boiler,  for  things 
go  wrong  when  they  are  least  expected  to.  In 
a  factory  where  hundreds  of  people  are  em- 
ployed, a  very  small  matter  to  an  engineer  may 
precipitate  a  panic  which  will  cost  many  lives, 
and  it  is  for  him  to  see  that  it  does  not  occur 
through  his  carelessness.  We  were  in  an  en- 
gine room — fire  room,  rather — once  when  a 
rivet  blew  out  above  the  water  line,  and  made 
a  great  fuss.  A  youth  who  was  in  the  place 


I2O 

started  for  the  door,  shouting  that  the  boiler 
had  burst,  but  he  did  not  get  far  enough  to 
frighten  others  before  he  was  caught  by  the 
collar  and  a  little  advice  given  him  that  was  of 
service.  When  a  rivet  blows  out  it  is  a  simple 
matter  to  whittle  a  pine  plug  and  jam  it  in  the 
hole,  either  above  or  below  the  water  line,  and 
it  is  not  a  bad  idea  to  have  plugs  handy  for  this 
purpose.  It  is  not  uncommon  for  rivets  to 
blow  out. 

Another  point  that  an  engineer  should  bear 
in  mind  is  that  the  engine  is  upon  no  account 
to  be  stopped  in  working  hours,  unless  it  goes 
to  pieces,  direct  orders  are  given,  or  danger  to 
life  and  limb  is  imminent.  No  engineer  should 
stop  a  factory  engine  where  goods  are  turned 
out  by  the  piece,  or  by  the  yard,  or  any  other 
quantity,  for  a  hot  bearing,  or  because  some 
detail  of  the  engine  will  be  ruined  if  kept  run- 
ning. The  cost  of  most  details  of  an  engine  is 
slight,  but  if  the  detail  costs  a  hundred  dollars 
it  is  better  to  lose  it  than  a  thousand  dollars' 
worth  of  work,  or  two  hundred  dollars'  worth 
of  time.  This  is  particularly  the  case  in  places 
where  power  is  sold  to  tenants.  Every  revolution 
of  the  engine  means  some  fractional  part  of  a 
dollar  to  them,  and  the  stopping  of  an  engine 
for  some  trifling,  or  possibly  serious,  expense 
to  the  landlord,  might  mean  ruin  to  a  tenant, 


121 

who  would,  perhaps,  depend  upon  that  very 
half  hour  to  complete  a  contract  in  a  given 
time.  Upon  trifles,  as  we  call  them,  very  great 
events  depend  sometimes. 

We  repeat  again,  never  stop  an  engine  in 
working  hours  except  for  the  direst  necessity. 
Also,  never  start  an  engine  after  it  has  been 
stopped  without  a  direct  written  message,  or 
direct  personal  notice,  from  the  man  in  charge. 
Suppose  nothing.  It  is  a  serious  business  to 
neglect  either  of  the  precautions  above  men- 
tioned 


122 


CHAPTER  XVIII. 
THE  HIGHEST  QUALITIES  DEMANDED. 

Finally,  let  me  say,  in  conclusion  of  this 
work,  that  the  duties  of  an  engineer  worthy  of 
the  name  call  for  the  highest  qualities,  and  are 
not  to  be  lightly  undertaken,  or  held  in  low  es- 
teem. A  man  who  stops  and  starts  an  engine 
is  not  an  engineer,  and  has  no  pride  in  his 
business,  because  he  knows  nothing  of  it ;  he 
does  not  wish  to  know  any  more  than  that 
opening  the  throttle  lets  steam  into  the  chest. 

But  we  should  not  be  discouraged  or  care- 
less ourselves  because  such  men  get  places,  to 
the  exclusion  of  their  betters.  There  are 
usurpers  everywhere.  Quack  doctors  abound, 
so  do  quack  ministers  and  shyster  lawyers.  It 
would  be  quite  as  logical  and  sensible  for 
skilled  professional  men  of  these  classes  to  give 
up  trying  to  rise  as  it  would  be  for  an  engineer 
to  follow  the  same  course.  Knowledge  of  our 
business  is  paid  for  always,  but  ar.  engineer 
must  know  where  to  find  the  best  market  for 
his  services,  exactly  as  every  other  man  must 
who  has  something  to  sell.  A  dentist,  let  us 
say,  settles  in  a  certain  locality  and  does  not 
thrive.  He  does  not  immediately  accuse  his 
profession  as  the  cause  of  his  trouble,  but  he 
says  that  there  is  no  business  in  that  place,  and 


123 

searches  until  he  finds  one  that  is  better. 
"  Knowledge  is  power"  is  as  true  to-day  as 
ever,  but  there  are  some  places  that  are  better 
than  others  to  sell  it  in. 

If  an  engineer  spares  no  effort  to  improve 
himself,  and  studies  first  principles  so  as  to 
know  where  to  look  for  the  cause  and  cure  of 
troubles  never  encountered  before,  he  is  a  bet- 
ter man  for  a  steam  user  than  a  mere  stopper 
and  starter  who  does  not  wish  to  learn.  Some- 
where there  is  a  steam  user  looking  for  him, 
and  it  is  the  engineer's  business  to  find  a  place 
where  he  is  paid  for  his  work.  We  need  only 
look  around  us  to  see  engineers  who  have 
good  homes,  are  socially  esteemed,  and  are 
bringing  up  families  to  be  a  credit  to  them- 
selves and  the  State.  These  men  started  from 
small  beginnings,  and  were  careful,  prudent 
and  anxious  to  learn.  They  did  learn,  and 
that  is  why  they  thrived. 

THE  MAN  HIMSELF  is  THE  FACTOR. 

It  is  not  the  business  which  a  man  follows 
that  keeps  him  down  or  lifts  him  up  ;  it  is  the 
man  himself  in  every  case,  and  it  is  well  to 
bear  in  mind  that  a  man  can  not  be  an  engi- 
neer, or  a  lawyer,  or  a  doctor,  or  anything  else, 
at  a  bound.  Long  service,  patient  waiting,  dis- 
appointments, reverses,  learning  through  them 
and  learning  by  success  also — all  these  have 


124 

their  perfect  work.  No  faithful  service  is  ever  lost. 
If  a  steam  plant  is  in  perfect  order  and  running 
lower  than  others  in  the  vicinity  be  assured 
that  if  the  employer  does  not  see  it,  others  do, 
and  perhaps  when  we  least  expect  it  we  may 
get  a  call  to  go  elsewhere  with  manifest  benefit. 
There  are  many  things  conducive  to  success 
in  engineering,  as  in  all  other  callings  which 
mankind  follow,  and  none  of  these  has  more 
effect  in  business  intercourse  than  a  pleasant 
address.  Engineers  are  commonly  supposed 
to  be  "  rough  men,"  but  after  living  and  asso- 
ciating with  them  for  forty  odd  years,  all  over 
the  United  States,  and  of  all  classes,  locomo- 
tive, stationary  and  marine,  we  have  found 
fewer  engineers  of  violent  manners  and  rude 
bearing  than  we  have  in  other  professions. 
Some  may  feel  that  civil  speech  has  little  to  do 
with  success.  It  has  everything  to  do  with  it, 
for  as  a  rule,  even  if  men  are  skillful  in  their 
special  line,  we  will  not  encounter  them  if  we 
can  avoid  it  when  they  greet  us  roughly  and 
are  surly  in  their  dealings  with  us. 

LASTLY. 

In  these  United  States  no  man  is  above  his 
calling  or  beyond  it.  If  he  is  a  man  in  all  that 
the  word  implies,  he  is  independent  of  circum- 
stances and  of  conditions,  and  is  always  in 
demand.  The  trickster  perishes  by  his  own 


I25 

sword.  It  does  not  take  long  to  discover 
whether  men  are  honest  or  the  reverse,  and 
once  the  verdict  is  given  either  way  no  one 
can  escape  the  consequences.  Not  merely 
honest  in  the  sense  that  he  will  not  take  what 
does  not  belong  to  him,  but  an  honest  man  in 
a  moral  sense.  And  with  this  little  sermon  we 
say  farewell. 


THE  CORLISS  EKGIHE. 

BY  JOHN  T.  HENTHORN. 
—  AND  — 

MINIGEMENT  OF  THE  CORLISS  ENGINE. 

BY  CHARLES  D.  THURBER. 
Uniform  in  One   Volume,   Cloth  Cover;  Price,  $1.00. 


Table  of  Contents. 

CHAPTER  I.— Introductory  and  Historical;  Steam  Jack- 
eting. CHAPTER  II. — Indicator  Cards.  CHAPTER  III. — 
Indicator  Cards  continued;  the  Governor.  CHAPTER  IV. 
— Valve  Gear  and  Eccentric ;  Valve  Setting.  CHAPTER  V. 
— Valve  Setting  continued,  with  diagrams  of  same;  Table 
for  laps  of  Steam  Valve.  CHAPTER  VI. — Valve  Setting 
continued.  CHAPTER  VII.— Lubrication  with  diagrams 
for  same.  CHAPTER  VIII. — Discussion  of  the  Air  Pump 
and  its  Management.  CHAPTER  IX.  — Care  of  Main  Driv- 
ing Gears;  best  Lubricator  for  same.  CHAPTER  X. — 
Heating  of  Mills  by  Exhaust  Steam.  CHAPTER  XI. — En- 
gine Foundations;  diagrams  and  templets  for  same.  CHAP- 
TER XII — Foundations  continued ;  Materials  for  same,  etc. 


Sent  free  by  mail  on  receipt  of  price. 


Egbert  P,  Watson  &  Son,  150  Nassau  St.,  N.  Y, 


A    FORTNIGHTLY    PATER    FOR    ENGINEERS, 

STEAM    USERS,    AND    ALLIED 

TRADES. 


TWELFTH    YEAR, 


Contains   useful   matter   of  the  class  indicated  by  this 

work,  and  treats  all  subjects  in  a  plain  matter 

of  fact    way,    without   pedantry    and 

without   pretense. 

Two  Dollars  per  Year  Always  in  Advance. 

EGBERT  P,  WATSON  &  SON, 

150  Nassau  Street,  New  York. 


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